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.

When will Google offer its much-discussed cellphone for sale?

Google says it isn’t planning to build or sell mobile phones. Instead, it is developing a cellphone operating system, or software platform, called Android. And it has assembled an alliance of companies, including phone makers and cellular network providers, to create phones based on this new platform. This group is called the Open Handset Alliance. In addition, since Android will be so-called “open source” software, Google expects numerous developers around the world, large and small, to modify the operating system and create programs that will run on it.

If all goes according to plan, Google says it expects to see many different Android-based cellphones and other mobile devices, from a variety of manufacturers and carriers, in various designs and with differing functionality and capabilities. Some may be larger-screen “smart phones,” similar to an iPhone or BlackBerry. Others might be smaller, simpler phones. Still others might fall somewhere between an iPhone and a small laptop.

Google officials say they expect the first Android devices to be available later this year.

After reading your Jan. 3 column, I looked unsuccessfully for a Home and Student version of Office for Mac 2004. Does such a version exist?

In the 2004 release of Microsoft Office for the Mac, this low-priced version had a different name: the Student and Teacher edition. Microsoft presumably changed the name of this $150 product to the Home and Student edition in both Office 2007 for Windows and Office 2008 for the Mac, because, while it was technically limited for sale to families containing students or teachers, no proof was required and it was widely purchased by consumers in general.

However, there’s a big difference between the latest Windows and Mac versions of the Home and Student edition. In the Mac version, it includes Word, Excel, PowerPoint and Entourage, Microsoft’s equivalent of Outlook on the Mac, which, like Outlook, includes email, calendar and contact functions. But the new Windows version now omits Outlook, and instead substitutes OneNote, a note-taking and information organizing program that is far less commonly used. So, Windows users must spend much more money to get a version of Office that includes Word, Excel, PowerPoint and Outlook.

Is there a way to back up Microsoft Outlook Express emails, particularly Inbox items?

Outlook Express stores your emails in database files, with all the messages in each of your mail folders lumped into a single such file. These files can be backed up, or copied, onto other hard disks, or storage media.

The email data files are usually buried in obscure subfolders in Windows. But you can locate them by clicking on the Tools menu, then Options. This will open a tabbed window. In this window, click on the tab called Maintenance, then the button called Store Folder. This will generally give you a long, complicated path to the folder.

Next, copy this path by selecting it and pressing Control and C. Then, click on the Start menu, select “Run…”, and then press Control and V and then click OK. This should open the folder that contains your email. The inbox is contained in a file called Inbox.dbx. This is the file you will want to back up. If you want to back up other folders, such as the Sent mail folder, you will find them along with the inbox file, with the same “.dbx” suffix.

Some backup programs may automate this process by simply allowing you to designate that you want to back up your Outlook Express emails. There are even some programs specially designed to back up Outlook Express messages. You can find some of these by simply performing a Web search on “backup Outlook Express.”

• 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.

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 free antivirus software, different versions of the Palm Treo and emails that claim to be from financial institutions.

My computer is a virus-infected mess. I sometimes have to close over 20 pop-ups just to access the PC. Taking your advice, I tried to download the “free” AVG Anti-Virus, but there is nothing free about it. They ask for your credit-card info. What am I missing?

The company that makes AVG, Grisoft, offers both paid and free versions of the product. The free version must be downloaded from a separate Web site, free.grisoft.com. Most of the first few results in a Google search for “AVG” or “AVG anti-virus” point to this free version. Also, the free version is prominently featured at Download.com, the big site for downloading software that is owned by CNET.

Is there a significant difference between the Palm Treo 700p and the 700w phones — or is it just preference of software? Do they have the same ease of use?

A. The 700p uses the Palm operating system and the 700w uses the Windows Mobile operating system. The hardware is essentially the same, except for one big difference — the 700p’s screen has a significantly higher resolution than the 700w’s. There are also some different buttons on the keyboard.

But asking if two devices differ in “just preference of software” is like asking if living in a similar home in North Dakota or Florida differs “just” in terms of your preference in weather. The software is every bit as important as the hardware, and makes a huge difference in how the two Treos work.

I have reviewed both devices, and I find that the Windows Mobile software on the 700w is considerably inferior to the Palm operating system software on the 700p. Too many common actions in the Windows version take more steps than the same actions on the Palm OS version, and often require navigating menus. You are likely to use the stylus more often in the Windows version as well.

And, even though the software on the Windows version was made by Microsoft, it is actually worse at handling Microsoft Office and Adobe PDF email attachments than the built-in software for that purpose on the Palm OS version.

For my review of the 700p, see: ptech.wsj.com/archive/solution-20060607.html. For my review of the 700w, see: ptech.wsj.com/archive/ptech-20060105.html.

Last week, you advised readers never to trust any email from a financial institution because online criminals have gotten so good at faking such emails. Does that include emails from institutions where you have accounts, such as receipts for transactions at brokerages?

Yes and no. If you get an unexpected email from a bank, or brokerage, or payment service like PayPal, where you do have an account, I’d still advise ignoring it and never clicking on any link it contains. This is even true if the email suggests some problem with your account or advises that you need to log onto a web site to “verify” your account information. Such emails are very often just attempts to steal your passwords and account numbers. To double-check on such an email, phone the bank or brokerage, or manually call up its Web site.

However, if you have just bought or sold a stock, or performed an online banking action, and you get an email confirming the transaction, it could well be legitimate — provided it contains enough detail of a type criminals might find hard to replicate, and it arrives very quickly after the transaction was completed. I still wouldn’t click on any links in such an email, however. Remember, most financial institutions don’t have to ask you to supply account information they already have.

It’s really too bad that people have to look on such emails with such suspicion. Email could be a great tool for communications between banks and their customers. But, despite some strides, the technology and financial industries have so far failed to find a way to make email truly trustworthy and secure. And law-enforcement agencies have failed to stop the thefts of money and identities. So far, the crooks are winning in this arena. So you have to be extra careful.

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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

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

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.

Do you think the Treo 650 will be the last true Palm OS-based mobile phone?

No. A new, improved Treo that uses the Palm operating system will be available soon. Palm (the hardware company that makes the Treo and other products) has said it isn’t abandoning the Palm OS (which is made by a separate firm) despite the fact that Palm now makes a Treo model that runs on the Windows Mobile operating system from Microsoft.

However, there is reason for Palm OS fans to be concerned. Although I regard Palm’s user interface as superior to Microsoft’s, the Palm system is relatively old and limited under the covers, compared with Windows Mobile. Its maker, PalmSource, came up with a prototype of a new version, but never completed it. Now, PalmSource has been acquired by a Japanese company, Access, that is said to be working on yet another new version of the Palm OS, based on Linux. Palm is optimistic about this project, but I haven’t seen it, and have no idea when it will appear.

Last week, you alluded to the fact that some Web-based calendars can synchronize with hand-held devices. Can you cite an example?

Yahoo provides Intellisync software that can synchronize its Web-based calendar, address book and notepad with Palm and Windows Mobile hand-held devices, as well as with such Windows PC programs as Outlook, Outlook Express, Lotus Organizer and ACT. For more information, see: help.yahoo.com/help/intsync.

Do you recommend using a registry-repair program on a Windows PC?

For most people, I don’t recommend fooling in any way with the Windows registry, which is a part of the operating system that contains important instructions for every program on your computer. It is quite dense and technical, and poking around in it can lead to dire consequences.

I know that there are registry-repair and editing programs that claim to be so safe and simple that anyone can use them, and it’s true that they are simpler than manually editing or repairing the registry. But I still advise mainstream users with little or no technical knowledge against touching the registry. If your computer is behaving badly enough that you’d consider trying to “fix” its registry, then it’s time to call in a pro.

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 troublesome email attachments and finding a hand-held mobile product that doesn’t include a cellphone.

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 use a Macintosh, and sometimes when a Windows user sends me an email attachment, it comes through as a file called “winmail.dat,” which can’t be opened. Is there a way around this?

Most attachments sent from Windows to the Mac come through fine, and vice versa. The situation you describe apparently occurs when the sender is using Microsoft Outlook and sends a “rich text” email that requires Outlook to decode. Since there isn’t a version of Outlook for the Mac’s current operating system, it comes through as a useless and mysterious winmail.dat file.

However, there is a free Mac program, called TNEF’s Enough, that can unlock the attachments buried in these winmail.dat files, so you can read and use them. You just save the unreadable attachment as a file on your hard disk, then open it in the free program, which converts it to a usable file or files. I have tested the program and it works well. It can be downloaded at: www.joshjacob.com/macdev/tnef/index.html.

Is there a hand-held mobile product that would enable me to surf the Web and attend to a few emails, using my home’s existing Wi-Fi system? I have several desktops and laptops, so I don’t need another computer, and I don’t want a cellphone. I just want something less cumbersome than a laptop.

A:Yes. Palm, Hewlett-Packard and others make PDAs (personal digital assistants) that don’t include cellphones but do include Wi-Fi receivers, email programs and Web browsers. Palm’s new $299 TX hand-held is a good example. So is HP’s iPAQ rx1955, which also is $299. Both have Wi-Fi Internet connectivity, large, bright screens and built-in email and Web-browsing software. The H-P is lighter, but the Palm’s screen has higher resolution. www.palm.com/us/products/handhelds/tx. Information on the H-P is at www.hp.com.

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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