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.

Do you still recommend the Dell XPS One all-in-one computer that you favorably reviewed last December? I am not a techie at all but need to replace my 5-year-old Dell and was interested in an all-in-one.

Yes. In fact, I now own two of these Dell XPS Ones and use them as my Vista desktop computers, at home and in the office. I still believe, as I wrote in my review, that this Dell’s hardware is superior to that of the competing Apple iMac, though the Vista operating system is inferior to Apple’s. And the base XPS One now costs the same as the base iMac — $1,199 — instead of $300 more, as it did last year. So, if you want the Windows operating system, and like the look and convenience of an all-in-one desktop, I still favor the XPS One. You can find my review at tinyurl.com/2xw 6mv.

Will Apple’s new MacBooks and MacBook Pros run Windows directly without an intervening “virtual machine” program like Parallels or Fusion?

Yes. All Apple Macs running the current Leopard operating system, including the new laptops, come with the ability to directly run Windows XP or Vista. Using Apple’s built-in “Boot Camp” feature, you can start up the computer in Windows, instead of the Mac’s own operating system, which turns the Mac into a pure Windows machine, with no trace of the Mac operating system running. The upsides of this approach are maximum Windows speed, and compatibility with the most graphics-intensive Windows programs, including games. Note that, to run Windows on a Mac, you must obtain and install a fresh, boxed, full version of XP or Vista. Apple doesn’t supply Windows.

I have a Yahoo email account, and wonder if Yahoo allows receipt and storage of email directly via a computer email program, such as Outlook, or is it all Web storage? Can you do both?

Yes. Yahoo offers a “Plus” option, for $20 a year, that permits users to receive and store their Yahoo email using a locally installed, instead of Web-based, email program. This approach does work with Microsoft Office, as well as many other local email programs. And you can still use Yahoo’s Web-based email interface at the same time. The Plus option also includes other benefits, including the elimination of ads and a doubling of the size limit on individual messages, to 20 megabytes.

• 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.

Is there a way to transfer a Windows Media music file to iTunes?

If the Windows Media file is copy-protected, typically because you bought it from an online store that copy-protects its music, iTunes cannot import or play it. However, if it is unprotected, which is typical for files you created from your own CDs using Windows Media Player, iTunes can import the file and automatically convert it into a format it can use.

I would like to purchase an iPhone, but run it on the Verizon network. I realize that AT&T has an exclusive at this time, but is there a way to do this on the secondary market?

No. The radio inside the iPhone is incompatible with the network technology used by Verizon and Sprint. That cannot be changed by hacking the software, or replacing the SIM card in the phone.

I need to buy a new laptop computer and am wondering if you think Vista is wise at this point or should I still stick with Windows XP if I can find it? I only do emails, browsing the net and some downloading of music and photos. I am retired and don’t know much about computers.

Vista easily handles the tasks you want to do, but it will require heftier hardware to work at acceptable speeds, and, assuming you are used to working with XP, Vista will require you to learn some new things. If you buy XP, you can get away with a more modestly equipped computer, and you will be working with a more familiar interface. So, in your particular situation, I would suggest an XP machine. But I urge you to make sure it gets upgraded to the latest revision, called SP3, which bolsters the security of XP, so it is closer to that of Vista. Depending on your setup, this upgrade may be delivered automatically by Microsoft, but you may have to agree to accept it.

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.