A: You will begin to see more touch-screen laptops after Oct. 22, when Windows 7 comes out, because that new operating system has optional fingertip touch-screen navigation built in. In addition, many of the major Windows PC makers are adding their own touch-navigation systems to newer models.

However, I’d offer two caveats. First, not every touch screen will be capable of performing all the multitouch actions and gestures Windows 7 will offer. Some are more limited in their capabilities.

Second, the hardware makers will likely be cautious at first about adding fully capable touch screens to all or most of their laptops.

This is partly because these screens can add significant cost in a price-conscious market, and partly because nobody is certain how popular touch-screen navigation will be on laptops as opposed to, say, on all-in-one desktops where reaching for the screen is more obvious and natural.

I have an Apple iMac, and an Apple iPhone with around 122 apps. My question is, why don’t these iPhone apps work on the iMac? Both units use the same operating system, so why not?

A: While the iPhone and the iMac each use a version of the same operating system, Apple’s OS X, they aren’t the same operating systems. The version on the iPhone is stripped down, and has been modified to support an entirely different user interface, navigation system and set of hardware capabilities.

So there are two separate collections of apps, or programs, that run on the two platforms.

I am currently running Windows Vista Ultimate on my Dell PC. I have regretted it ever since I upgraded from XP because of its terribly slow performance. I have heard good things about Windows 7 but I am afraid I will have to buy the more expensive Ultimate upgrade (which I don’t really need) instead of an upgrade to Home Premium or Professional. Is that true?

A: According to Microsoft, owners of Vista Ultimate can only perform an “in-place upgrade” to Windows 7 Ultimate, not to lesser versions. An “in-place upgrade” is the type most people think of, the type where all your programs and files and settings are preserved just as they were, but you emerge with the new operating system.

Even then, you must be careful to buy the edition of Ultimate that matches the type of architecture your machine possesses, either 32-bit or 64-bit.

However, you can downgrade to the Home Premium or Professional versions of Windows 7, if you are willing to do a lot more work, by opting for what Microsoft calls a “custom installation,” something commonly known as a “clean install.” This typically means, first, backing up all your files and settings to an external hard disk, then allowing the Windows 7 installation disk to wipe your hard disk clean before installing your preferred version of Windows 7.

You would then copy back all your files. But you cannot do the same with your programs. For these, you would have to reinstall every one, from their original disks or downloaded installation files, and then download and re-install all the patches and program upgrades that have been issued by their makers since you acquired them.

You can find Mossberg’s Mailbox, and my other columns, online for free at the All Things Digital Web site,

http://walt.allthingsd.com.

In your spring buyer’s guide, you wrote that adequate graphics chips will be more important than ever, but in the past you’ve advised that memory, or RAM, was key to speed and performance. Can you now get the same gains by buying or adding a better graphics chip? Or is RAM just as important as ever?

There are lots of things that can improve the performance of a PC or Mac. But adding memory still gives you more bang for the buck than any other, in my view. What I was saying last week is that the forthcoming Microsoft and Apple operating systems will be relying more on graphics chips to help take some of the load off the main processor and speed up certain tasks. Even so, a better graphics chip isn’t a substitute for more main memory. In fact, most moderately priced computers use so-called integrated graphics chips, which lack dedicated memory and share some of the computer’s main RAM. So having plenty of main memory is directly related to getting the most out of such graphics chips.

Can the iPhone be connected to desktop peripherals? I want to be able to plug my iPhone into a large monitor and printer.

There are already several apps, including one from Hewlett-Packard, that allow you to print photos wirelessly from an iPhone to a printer that’s connected to a Wi-Fi network. But, as far as I know, there is nothing on the market today that can connect an iPhone to an external monitor or keyboard, or to a printer for nonphoto printing. However, Apple has announced that the new 3.0 version of the iPhone operating system, due this summer, will enhance the ability of the iPhone to work with add-on hardware, either via cables or wirelessly. The company showed this off with medical devices, but it’s possible that some third party could make it work with monitors or printers or keyboards.

A recent article in the Journal reported that a person had installed the Mac operating system on a Windows laptop. Is this really possible and is it legal?

Apple doesn’t sell or license its Mac OS X operating system for use on non-Apple hardware. In fact, the company considers it illegal to install OS X on other brands of computers. Nor does it produce OS X drivers for non-Apple hardware features that are built into competitors’ computers. Nevertheless, some computer hobbyists have installed OS X on non-Apple hardware, and posted photos and videos online to prove it.

Even if you are willing to ignore the legal issues, this process, while not brain surgery, takes more skill than the average user possesses. And, in the end, some features of the computer may wind up disabled or require workarounds to function. For instance, on one such machine I saw, the speaker port didn’t work with the Mac OS.

• 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.

I read your recent column about running Windows on a Mac. Is there a way to run the Mac OS X operating system on a PC, like a Dell or a Sony?

Yes, but it is really only for tinkerers and hackers, and even then, it may not work fully or smoothly. Apple makes the process difficult, both technically and legally, because, unlike Microsoft, it is not in the business of selling its operating system for use on other companies’ hardware.

Therefore, I know of no simple software for average consumers that can install OS X on a non-Apple computer without any technical knowledge and with full assurance that the operating system will be completely compatible with the hardware. There is nothing on the market like the products that allow people to run Windows on a Mac.

A small number of techies do install Mac OS X on non-Apple PCs every day, and some people have created software to make this possible for people with plenty of technical knowledge. There is even a company called Efix that is selling a hardware module that it says will make this easier. Its maker warns the product is only for “enthusiasts” and it requires that you attach it to the computer’s internal circuitry. Also, it only works with certain types of personal-computer hardware.

One more thing: Apple takes the position that its licensing terms limit the use of OS X to Apple hardware, so, even if you can pull it off technically, there could be legal jeopardy involved. In fact, Apple is suing a company called Psystar that sells non-Apple PCs with OS X pre-installed.

I have a new PC that came with a 64-bit version of the Windows operating system. It gives me a choice between using a 32-bit Internet Explorer or a 64-bit Internet Explorer. Which should I use?

The 64-bit version of Windows, which is rarely used by average consumers, can make the computer faster, but only when running programs that have been written in special 64-bit versions. In the consumer arena, there are too few such programs, and thus too little benefit, to justify paying extra for 64-bit machines. In fact, most people who have computers running 64-bit Windows are mostly using older 32-bit programs, which run fine, but aren’t made quicker.

So, the 64-bit version of Internet Explorer may run faster. But there is a downside. Because of the relative rarity of 64-bit users, some browser add-ons and toolbars and some of the Web technologies that power the features of Web pages, aren’t compatible with the 64-bit version of IE. On top of that, you may not notice any huge speed difference as the perceived speed of Web browsers depends more on the speed of your Internet connection than anything else. So, for now, I would stick with the 32-bit version, for compatibility’s sake. You can always install the 64-bit version later, if you decide that the Web sites you frequent and the add-ons you use work well with it.

I am running a Mac with Windows XP Pro in Boot Camp, which requires rebooting to change operating systems. Is there some way I can use my already-installed Boot Camp setup as a virtual machine using VMWare Fusion, so I can run my Windows and Mac programs side by side?

Yes, there are two ways. First, Fusion allows you to treat the Boot Camp section of your hard disk, called a “partition” — which is essentially a separate Windows PC stored on your Mac — as if it were a “virtual machine.” This approach still allows you to reboot the entire Mac into Windows when you’d like to do so, in order to perform the few tasks that Fusion can’t handle, such as advanced 3D graphics.

The second approach is to simply import the Boot Camp installation and turn it into a purely virtual Windows computer, as with any virtual Windows machine you would create in Fusion. If that meets your needs, you can then actually remove your original Boot Camp Windows installation, which will likely free up some hard disk space. To do this, just select your Boot Camp partition, which Fusion automatically detects, and click on Import under the File menu.

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

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

I have moved from a PC to the iMac. In the Windows environment, I felt a need to run utilities to clean out the registry and defragment the hard disk frequently. Is this also needed on the iMac? If so, what programs are recommended?

The Mac operating system, called OS X Leopard, doesn’t include a registry, which is a feature of Windows that holds information that programs need to operate properly. So there’s no need to clean or maintain any registry on a Mac.

Mac hard disks, like those on Microsoft (MSFT) Windows computers, can get fragmented — a condition in which parts of files are so scattered around on the disk that the disk runs slowly. However, the operating system has some under-the-covers features that generally obviate the need to run a defragmentation utility. In fact, Apple (AAPL), which calls defragmenting a disk “optimizing” it, flatly claims that “You probably won’t need to optimize at all if you use Mac OS X.” There are some Mac defragmentation utilities, but I don’t believe you will need them unless you have large numbers of extremely large files and almost no free disk space.

My son’s computer frequently gets infected with adware, pop-ups. Recently it was hit with a continuing pop-up ad called VirusHeat that touted itself as a solution to the computer’s problems. When I paid for VirusHeat, the problems went away. Is it legitimate?

According to numerous reports on the Web, including some from security companies, VirusHeat is a form of malicious or misleading software. It falls into a category that attempts to scare people into thinking their computers are badly infected, or exaggerates any problems you may have. This is a common tactic now used by creators of malware.

Some of these fake or misleading “security programs” may be designed merely to make you pay. Others may even be designed to install the very kinds of viruses, spyware or adware that they claim to fight.

I have updated to a new PC. My data are on a floppy disc. There is no floppy disc drive on this new computer. How can I transfer my data?

For around $25, you can buy an external floppy disk drive that plugs into a new PC using its standard USB port. If you do so, and connect it to the new PC, you should be able to copy your data to the new computer’s hard disk.

• 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.

We are connected to Comcast (CMCSA) cable and use no antennas. Will we need one of the government-subsidized converter boxes next February?

Not if you are using a cable set-top box, like the vast majority of cable customers. If you are one of the minority of cable households whose TVs use an internal cable tuner, you may need a converter box. To be sure, contact your cable company or TV manufacturer.

In your laptop buying guide last week, you recommended buying a machine equipped for the “n” type Wi-Fi of wireless router. I was under the impression that this has not yet been standardized. Is that wrong?

The engineering committee that has been debating the standard for years has not yet completed its work, but the market has simply moved ahead on its own. This new, faster version of Wi-Fi is being built into routers, computers and other devices by nearly every major manufacturer. In my limited tests, I have found no compatibility problems, and it is backwards compatible with the older “g” and “b” standards.

Is the Mac immune to viruses? If not, do you have a recommendation of the type of antivirus software one should procure and load onto a Mac?

No personal computer or personal computer operating system of which I am aware is “immune” to viruses, spyware or other malicious software. That includes Apple’s (AAPL) Macintosh and its operating system, Mac OS X Leopard. Hackers have demonstrated the ability to invade the Mac. However, there are only a handful of viruses or other malicious programs for the Macintosh that have successfully spread beyond the lab. And these have harmed only a small number of actual users.

Of the well over 100,000 known viruses, spyware programs and other malicious software applications that are about in public, all but this handful are written to run on Microsoft (MSFT) Windows, and cannot operate on the Macintosh OS. For that reason, I don’t believe Macintosh owners need security software, unless they install and run Windows on their computers. If they do run Windows, Mac owners are well advised to purchase and install Windows security software to protect the Windows portion of the machine.

Having said that, I do not mean that Mac owners should be blind to security threats that don’t involve viruses or spyware. Just like Windows users, Mac users can succumb to what is called “social engineering” — scams and schemes that operate via email and Web sites that are often authored by crooks but made to look official. So, like Windows users, they must be on their guard.

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

I couldn’t find any columns on products you recommend for monitoring kids’ Web access and installing parental controls. I recently purchased a new computer for my 9-year-old daughter. I want to make sure she can only access specific Web sites and I want to protect her from inappropriate spam and chatting.

If you have a computer running one of the newer versions of Windows or the Macintosh operating system, I recommend using the extensive parental controls that are now built right into those operating systems. While you can never underestimate the ingenuity of computer-savvy kids, these built-in controls, if properly used, are generally harder to evade than the ones provided by third-party software.

I did recently review these built-in parental controls, which appear in Windows Vista, and in the Tiger and Leopard editions of the Mac’s OS X operating system. You can find that column at: ptech.allthingsd.com/20070614.

I want to switch to a Mac, but my life is on Microsoft Outlook, which is only available on Windows. Is there a simple way to convert all of this data to programs on the Mac?

There is a $10 program that performs this task. It’s called O2M (Outlook to Mac) and is from a company called Little Machines. It can be downloaded at littlemachines.com, where you also will find details about the Mac programs with which it works. This is a Windows program, which transfers your Outlook data into files you copy to your Mac. You then manually import these files into your Mac programs.

According to the company, the program exports Outlook email, email attachments, contacts and calendar appointments and allows you to import this data into Apple’s built-in email, address book and calendar programs, as well as into Microsoft Entourage, and other third-party programs.

Another approach is to install Windows on your Mac, and keep running Outlook. If you do this using the Parallels or Fusion virtualization programs ($80 each, plus the cost of Windows,) you can run Outlook simultaneously with your Mac programs.

Does the new version of Microsoft Office for the Mac work on pre-Intel Mac models?

Microsoft says it does, though I didn’t test it on one of these older machines. According to Microsoft, the new Office 2008 runs on any Mac “with an Intel, PowerPC G5, or PowerPC G4 (500 MHz or faster) processor.” However, you also need a relatively recent version of the Mac operating system, either the new Leopard edition, or the latest update (called 10.4.9) of the Tiger edition.

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.

Apple makes beautiful hardware, and, in my experience, it runs Windows quite well. In fact, the mouse and keyboard problems you cite are easily overcome, since you can plug almost any USB keyboard and mouse made for Windows into a Mac and they will work fine, right-mouse button and all.

However, what makes a Mac a Mac is primarily Apple’s OS X operating system, and the software Apple bundles with it, the iLife suite. If you don’t intend to use that, I don’t see much point in buying an Apple computer. You won’t get the advantage of the Mac’s lack of viruses and spyware, which stem from the operating system, not the hardware. And you can buy a Windows computer for less than the least expensive Mac.

In my view, the main value of the Mac’s ability to run Windows is that it allows Apple owners to use the few Windows programs they require or prefer that lack Mac equivalents, while primarily running the Mac operating system and programs designed for it.

How can one send an email to a group of people without all of their individual email addresses showing?

The most common method is to put your own email address in the “To” field and the names of all the recipients in the “Bcc” field, which is designed to be invisible. There’s always a danger someone quickly scanning just headers will decide not to read the email, since it isn’t addressed to her, but most email veterans understand the technique.

Is there a way to regain the traditional drop-down menus and other interface items in the new, redesigned Microsoft Office 2007?

There is at least one third-party add-in program designed to do this, but I haven’t tested it. It’s called Classic Menu for Office 2007, and can be found at www.addintools.com.

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.

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