In your recent Firefox review, you said Internet Explorer has a private browsing mode that doesn’t record your history or tracks while surfing. But I can’t find how to turn it on.

The feature, which is called InPrivate Browsing, is only available in the latest version of IE, called IE8. You turn it on by either selecting that option from the Safety button at the upper right, or from the Tools menu in the Menu Bar if you have chosen to make that bar visible. Once you do, an “InPrivate” label appears at the top left corner of the browser and a page appears explaining that the browser won’t record on your own PC certain records of what you do in that browsing session. There’s an additional privacy mode, available from the same two drop-down menus, called “InPrivate Filtering,” which goes further. It blocks Web sites you go to from saving certain records of your presence there on their own servers. InPrivate browsing lasts until you close the InPrivate browsing window.

When you reviewed the latest Safari Web browser awhile back, you complained that Apple had repositioned the tabs in a way that made them harder to see. A friend said that’s no longer true. Is he right?

Yes. After getting a lot of negative reaction, Apple changed Safari 4’s design so the tabs are displayed in the previous manner, below the toolbar, instead of at the very top. The company also made more visible the page-loading indicator, though I personally still prefer the indicator style used in prior versions.

In your column last week, you recommended add-on software to search documents for key words in Windows XP. Is there any similar software that will do the same for Macs?

It’s unnecessary on Mac because the Mac operating system comes with a fast, comprehensive search system called Spotlight that’s built right in. Windows Vista also has a very good search system built in. The reason I recommended add-on software for Windows XP is that I consider XP’s built-in search to be slow and inferior to those in these two newer operating systems.

You can find Mossberg’s Mailbox, and my other columns, online for free at the All Things Digital Web site, http://walt.allthingsd.com.

After reading your positive review, I downloaded Firefox 3.0, only to discover that some of my favorite add-ons, including a search toolbar, are incompatible. What can I do about this?

Wait. As I noted in the review, when major new versions of Firefox come out, it takes a while for some of the many add-ons for the browser to be updated so they are compatible with the new version. Because these are written by a very large number of different companies and individuals, the process will be gradual, and some will be updated more quickly than others.

As for search toolbars, like those from Google (GOOG) and Yahoo (YHOO), I doubt that most people still need them. When they first came out, these toolbars provided things the top browsers lacked: a permanent search box, pop-up blocking and a few other useful features. But all the major browsers now provide these things without requiring the installation of any external toolbar. The companies that make the toolbars can use them to sell advertising or attract you to their search engines. But, for many users today, they are redundant.

I don’t want to run antivirus software constantly, but I would like to periodically run a program that could scan my computer and remove viruses and the like. Does such a program exist?

Yes. Here’s one example. Microsoft (MSFT) makes a small, free program called the Malicious Software Removal Tool that looks for, and tries to remove, a limited number of the worst examples of malicious software. It can be downloaded at www.microsoft.com/security/malwareremove.

However, this isn’t a comprehensive antivirus program. Microsoft says it detects and removes only “specific, prevalent malicious software,” and advises that “You should also use up-to-date antivirus software to help protect your computer from other malicious software.”

I am in the market for a laptop. I was considering a Dell (DELL) or an H-P (HPQ) but have learned that Apples now run Windows. I have financial (Quicken) and other business files (Excel, Word and PowerPoint) that would need to be transferred to the new computer. Would this be possible on an Apple (AAPL)?

Yes, in the same ways you could transfer files from one Windows PC to another. For example, you could burn them to a CD or DVD, copy them to an external USB drive, or transfer them over a network or via the Internet. In fact, if you buy your Mac at an Apple retail store, the store’s staff will move your files over free, or for a modest fee, depending on which folders, and how many, you want transferred.

Once the files are on the Mac, you can either use native Mac programs to read and/or modify them, or you can install Windows and run your usual Windows programs to handle the files.

For instance, even if you never installed Windows on an Apple, your Excel, Word and PowerPoint files could be used in the Mac version of Microsoft Office. However, the Mac version of Quicken isn’t as compatible with the Windows version’s files. So, for Quicken, I suggest installing Windows on the Mac and running the Windows version of Quicken.

• You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital web site, http://walt.allthingsd.com.

Last week, when you wrote about the ChaCha cellphone search service, you didn’t say how they make money. Are they collecting phone numbers from customers so they can send spam text messages, or sell the numbers to others who will do so?

ChaCha allows you to ask any Web-searchable question, by speaking it or texting it over a mobile phone, and then it sends you the answer via text message. The company charges consumers nothing, but says it is hoping to make money by striking deals with cellphone carriers to incorporate the ChaCha service into their current 411 phone-number look-up services. Also, it hopes to eventually include ads in the text message answers it provides.

In addition to the message that includes the answer, ChaCha sends you a message saying it is working on your request and restating your question, so you can see if it understood you correctly. It also sends an introductory text message to first-time users and occasional tips on how to use the service. Scott Jones, ChaCha’s chief executive, asserts that “we do not spam” and “we never make phone numbers and/or email addresses available to others.” He said the company is updating its privacy policy to make that clearer.

We have DSL service. I use several Web-based applications, one of which is online backup, and my husband is concerned that they degrade his use of the Web, which includes creating Web sites. I contend that that is like saying turning on one light bulb is using too much electricity, that two people on one DSL line aren’t using up too much bandwidth. Who is right?

Every situation differs, depending on exactly which programs you are each using, how you have them set, whether you are using them simultaneously, and how fast your DSL connection is. However, in general, your husband is correct that it is possible for heavy Internet usage on one computer in a home to slow down Internet speeds on another.

This is especially true with something like online backup, because it relies on your DSL account’s upload speed, which is typically far slower than the download speed. If your online backup program is trying to push a bunch of files over a slow upload connection, while he is in another room trying to upload new versions of a Web site over the same narrow upload pipe, it could affect the speeds he gets. You might try coordinating or staggering those online activities that involve heavy uploading. Normal Web surfing or emailing shouldn’t require any such coordination.

I am thinking about purchasing a Dell (DELL) XPS One all-in-one desktop, but I have one question. Does the Dell’s built-in TV tuner require any extra attachments to watch TV right out of the box?

You can watch over-the-air stations and analog basic cable stations right out of the box, without added equipment. However, you may want to connect a small desktop antenna to improve reception, which is what I did when I tested this machine. To use the XPS One with digital or premium cable or satellite stations, you would have to connect it to a cable or satellite receiver, just as most people do with their TV sets. This requires the use of an adapter that comes with the machine.

• You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital web site, http://walt.allthingsd.com.

There’s no other major item most of us own that is as confusing, unpredictable and unreliable as our personal computers. Everybody has questions about them, and we aim to help.

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability.

Last week you discussed how to uninstall Windows Vista and go back to Windows XP. But I own a Macintosh, and after upgrading to the new Leopard operating system from Tiger, I find I dislike Leopard. How can I uninstall Leopard and go back to Tiger?

To restore the older Tiger operating system after upgrading to Leopard, you should first find the Tiger DVD that came with your Mac. Insert it and reboot your Mac while holding down the “C” key. This will boot the computer from the DVD rather than your hard disk.

On the screen that shows available hard drives for installation, click on the Options button and select the “Archive & Install” option. Also, select the choice called “Preserve Users & Network Settings.” If you have enough free disk space (roughly six gigabytes), Tiger will be reinstalled and your home directory and applications should be preserved.

However, just as with Windows, performing such an operating system “downgrade” on a Mac can be tricky for a nontechnical user. You might want to hire an expert to do it. If you do decide to try it yourself, I strongly urge you to first read an Apple document that contains more details, including some potential pitfalls and limitations of the “Archive and Install” procedure. It’s at http://docs.info.apple.com/article.html?artnum=107120.

Occasionally, I try to download a song or artist that would be in the “Easy Listening” category, but neither iTunes nor Amazon lists that genre. How can I find them?

In the iTunes store, there is indeed a genre called “Easy Listening” that contains thousands of tracks. The problem is that it’s not listed on the front page of the store. To find “Easy Listening” and the songs it contains, select “Browse” from the box labeled “Quick Links” at the upper right on the store’s front page. Then click “Music” in the far left column and “Easy Listening” in the column labeled “Genre.”

In Amazon’s MP3 download service, I couldn’t find a listing for the “Easy Listening” genre. But some of the songs and artists you’re looking for could be listed under other categories. Try directly searching for an artist’s name or a song title in the search box at the top of the MP3 Downloads page.

Why isn’t a FireWire port included on either of the two new slim laptops you recently reviewed, the Lenovo ThinkPad X300 and the Apple MacBook Air?

Both laptops are so small that they can only include a limited number of ports, though the Lenovo has many more than the Apple. And standard FireWire, also known as “1394″ or “iLink” on some machines, is becoming redundant in mainstream consumer computers, since the USB 2.0 ports offer roughly the same speed and are compatible with many more devices. There is a faster version of FireWire, which Apple uses on most of its desktop models. But there is also a faster version of USB in the works.

You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.

Corrections and Amplifications

Due to incorrect information provided by the manufacturer, this column erroneously says that Macintosh users performing a “downgrade” from Apple’s new Leopard operating system to the older Tiger system should select an option called “Preserve Users & Network Settings.” In fact, that option isn’t available when installing an older version of the operating system over a newer one. Users must instead manually relocate their data files and settings after performing the downgrade, a process that is explained at this Web page: http://docs.info.apple.com/article.html?artnum=107297.

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about recovering deleted icons, clearing search histories and the difference between laptop processors.

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

I accidentally deleted from my Windows XP desktop the icon for a program I use often. I know that this doesn’t mean I have deleted the program. But how do I get its icon back on the desktop?

There are multiple ways to do it, but here are a couple. You can click on the Start Button, then on All Programs, then locate the entry for the program, and just drag that entry onto your desktop. Or, you can locate the program file itself (it’s typically in a subfolder of the Program Files folder), select the file, click the right mouse button and then click on “Send To.” From the next menu that appears, select “Desktop (create shortcut).”

In the Firefox Web browser, how do I erase all traces of my browsing activity, so another user of the same computer can’t see what I’ve been doing online?

Go to the Tools menu, and select “Clear Private Data…”. This will bring up a list of traces that can be expunged. You just check off the ones you want obliterated, and then click on the button at the bottom labeled “Clear Private Data Now.”

To be absolutely safe, you can check off the entire list, but, generally speaking, clearing the browser history, download history, cookies and cache should hide your tracks from a casual user.

Be aware that there’s a downside to this. After clearing out this stuff, your Web surfing could slow down a little, because you won’t have any cached pages for the browser to use to speed up the loading of sites you’ve visited in the past. Also, by purging all cookies, you will lose the automatic log-ins and saved preferences, from some sites.

I am shopping for a laptop, and am confused by some of the processor choices. Specifically, what is the difference between Intel’s new Core Duo chip and the Core Solo chip?

Both are new designs, which combine power with greater efficiency. They run cooler than older processors, thus allowing for thinner laptops, fewer fans, and, in some cases, better battery life. But the Core Solo is, like most past processors, a single digital brain. The Core Duo packs two brains — two “cores,” each the equivalent of a single processor — onto one chip. This potentially offers greater speed in performing tasks on the computer, especially when you are running several programs at once, and especially if one or more of the programs is demanding.

Bear in mind, however, that to get the most out of the dual-core design, your software should know how to use the twin cores. Not all software does, though this should improve over time, as software is revised to better use the new chips. Also, the overall performance of a computer depends on many factors beyond the processor. These include how much memory you have, the power of the video subsystem and the speed of your Internet connection.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

You recently recommended antispyware programs for Windows users. Do Apple Macintosh users need such software, and, if so, what products clean up spyware on the Mac?

There’s little or no reported spyware for Apple’s Mac OS X operating system. So the spyware problem isn’t much of a headache for Mac users, and consequently, there isn’t much of a market for Mac antispyware software.

Most spyware and adware consists of malicious programs, and, like regular programs, these harmful applications have to be written to run on a particular operating system. All the spyware programs I have seen, or heard about, are written to run on Windows, which is on the vast majority of the world’s PCs, and is also easier for spyware programs to penetrate than the Mac operating system is. Because they are Windows programs, they simply won’t run on the Mac, even if Mac users accidentally download them.

One type of spyware, called tracking cookies, doesn’t take the form of an actual program, and can be used on Macs. There are a few antispyware and cookie-control utilities for the Mac that may be effective against these tracking cookies, such as Internet Cleanup from Allume Software (www.allume.com). But, unlike their Windows counterparts, I haven’t tested any of them, and can’t say how well they work.

Mac users who run Apple’s built-in Safari Web browser can stop most tracking cookies by going to the Security portion of the Preferences panel and selecting the option to accept only cookies placed by the site they are using, which eliminates cookies placed by third-party advertising companies. A similar option is available in the Firefox Web browser, on both Mac and Windows. On the Mac, it’s in Firefox’s Preferences panel, under Privacy.

I’m at a loss as to where to find blogs on the Web. Are there blog search engines that help compile and categorize blogs for public perusal?

Yes. You can search or browse Web logs, or blogs, at several sites such as Feedster (feedster.com), Bloglines (bloglines.com) and Technorati (technorati.com).

You can also install special programs that let you find, and subscribe free of charge, to numerous blogs and other frequently updated Web sites. These include FeedDemon for Windows (feeddemon.com) and NetNewsWire on the Mac (ranchero.com/net newswire/).

With these programs, called news readers, you don’t usually see the blog in its original form, you receive “feeds” from them — constantly updated headlines and summaries of new entries. You can then read the entire item by just clicking on the headline.

I’ve been shopping for a TV that can receive broadcast high-definition signals, and notice many described as “HD-ready.” What does that mean?

To receive and display high-definition programming, a TV set needs two basic features. One is a display capable of rendering the high-definition picture. The other is a tuner, or receiver, capable of receiving the high-definition signal, either over the air, or from a cable or satellite service.

When a TV set is described as “HD-ready,” it usually means the set can display high-definition pictures, but lacks the special tuner needed to receive them. It may have no tuner at all built in, or it may have just a standard tuner. With this type of TV, you must buy a separate high-definition over-the-air tuner, or obtain a high-definition cable or satellite receiver, to get high-definition programming.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

I am moving from an old Dell with Windows XP to a new one. I want to move over a wonderful picture of a covered bridge that I use for my desktop. It has family significance, and it’s my only copy. But, I can’t find the bridge picture anywhere. I didn’t keep all my photos in the “My Pictures” folder and have no idea where they all are.

If you go to the Display control panel, select the Desktop tab and highlight the name of your bridge picture (which should be listed there), and then click on Browse, you may see the folder where the picture resides.

This doesn’t always work. If it doesn’t, because this picture has personal significance for you, I suspect it would be worth it for you to spend some time and effort to conduct a thorough search. And, since the built-in search in Windows is awful, I suggest you download and install one of two free search programs that can find pictures anywhere on your hard disk and show you a preview of them.

Both Yahoo Desktop Search (at desktop.yahoo.com) and MSN Desktop Search (at toolbar.msn.com) meet that description (the popular Google desktop search has no preview feature). They require time to index your hard disk, but, once they do so, they should be able to locate and find your bridge picture.

Is there any way I can copy the address book used by Outlook Express so I can move it to a second computer?

Yes. The address book is contained in a file whose name is usually your user name, followed by a period and the letters “WAB,” for Windows Address Book. It usually resides deep in a subfolder in the Documents and Settings folder.

To find it, use the built-in Windows search system (it’s weak, but can do this particular task) or a third-party search program to search for “WAB” or “.WAB”. It should come up. Once you find it, you can just copy it like any file to a removable medium, like a writable CD or a USB thumb drive, or even email it to yourself.

When you copy it to your new computer, remember where you placed it. Then, open Outlook Express on the second computer, and open the address book by going to the Tools menu and clicking on Address Book. Go to the address book’s File menu, select Import, and click Address Book (WAB). Navigate to the address-book file that you copied from the first PC, and then click Open.

Why do you recommend using antispyware software to get rid of tracking cookies? Isn’t it more effective to just use the cookie-management features of a Web browser to delete these cookies or block them in the first place?

No. The cookie-management features in popular browsers don’t distinguish between tracking cookies, a type of spyware that records your activities online, and the many helpful cookies you probably want to keep, like those that store your login information or preferences on a site. Some allow you to block or delete only “third-party” cookies, which might trap some tracking cookies placed by Internet advertising firms who aren’t the actual operators of the Web sites you visit. But this may not always work.

Instead, I recommend using a good antispyware program, which every Windows user should be running anyway. These programs aren’t focused on cookies in general, but on every kind of computer code, including tracking cookies, that qualify as spyware and adware. They detect tracking cookies by maintaining lists of the most common ones, and they update this information constantly. They leave nontracking cookies alone.

Of course, you could use both methods. You could set your browser to reject third-party cookies (assuming that this doesn’t impair your browsing experience) and still run regular spyware scans to catch any tracking cookies that still make it through.

Write to Walter S. Mossberg at mossberg@wsj.com