This week, Microsoft is releasing Windows 7, a slick, much improved operating system

If you've been holding off on buying a new computer, Windows 7 will be a good excuse to get back into the game. And if you've been weighing a Mac versus a Windows PC, then you should know that "7'' makes Windows more attractive, though not a clear-cut choice for everyone. Windows is now easier to use and better looking than it was before, while maintaining its core advantage of cheaper, more diverse hardware.

Windows 7 will come in several versions. The one aimed at U.S. consumers is Home Premium, which will cost $120 if bought as an upgrade to XP or Vista. You can buy it as a download or on a disc. Beginning on Oct. 22, it will come installed on new PCs.

Here are highlights:

- The taskbar - the strip of icons usually found at the bottom of the screen - now does more than show which programs are running. You can also stick icons for your favorite programs on it, to launch them quickly. It's fast and convenient, combining the best features of the old Windows taskbar and Apple's Dock.

- File folders can now be organized into "libraries." You can have a photo library, for instance, that gives you quick access to pictures in folders spread out over your hard drive, or even several hard drives. This is great because many applications don't automatically put files into Microsoft's My Documents and My Photos folders, and tend to deposit content in their own folders. The new arrangement also makes for easy backups.

- Like Vista, Windows 7 will ask you twice if you really want to make changes to your settings or install programs, for the sake of security. But Windows 7 does it less often, and the prompts can be turned off.

- Windows 7 can sense if you use more than one finger on your touch pad or touch screen, allowing for neat tricks such as spreading your fingers to zoom into a picture, just like on the iPhone. This is isn't revolutionary per se - computer manufacturers have bolted multitouch sensing on previous versions of Windows. But it does make it easier for them to include advanced touch capabilities, and many of them are planning to do so. That is what could really revolutionize how we use computers. I've tried laptops and desktops with touch screens, and found it nice to be able to directly tap links and buttons, bypassing the touch pad and mouse.

- For a lot of users, the step up to Windows 7 will also mark a transition to a 64-bit operating system. That means computers will now be able to use a lot more Random Access Memory, or RAM, for better performance in demanding applications such as video editing. Vista and XP came in 64-bit versions in addition to the regular 32-bit versions, but the XP version was never popular, and the Vista version became mainstream only last year. But 64 bits will be standard on Windows 7, installed on nearly all new computers.

Windows XP users have a lot more to gain by going to Windows 7. Vista introduced some great features, such as fast searches of the entire hard drive, that of course are present in 7 as well. Unfortunately, upgrading an existing PC from XP to 7 is not easy.
After upgrading, users will have to reinstall all their programs and find their files in the folder where Windows 7 tucks them away.

They may also have hardware problems. I found an old HP laser printer no longer worked with Windows 7. This isn't really Microsoft's fault or, specifically, a problem with the new operating system - HP just doesn't provide a 64-bit driver for that printer. A driver is a program that tells a piece of hardware how to work with an operating system.

If you do upgrade, I would still recommend tackling that transition head-on by installing the 64-bit version of Windows 7, which doesn't cost more. Microsoft recommends a minimum of 2 gigabytes of RAM to run it.

If your computer runs Windows Vista, I think it's hard to justify spending $120 for an upgrade. The new features are nice but hardly must-haves. For daily e-mail and Web surfing, they won't make much of a difference. Vista was much maligned when it arrived in early 2007 for being slow, buggy and annoying. Now, it really isn't that bad, because updates have fixed a lot of the problems.

However, if you bought a Vista-based computer after June 25, you should be eligible for a free upgrade to Windows 7 from the manufacturer, and I suggest taking advantage of it. Your computer likely already is running 64-bit software, so there should be no problems with drivers, and the upgrade is much easier than one from XP. Windows 7 can keep your installed programs and your files in their old folders.

In weeks of testing the final version of Windows 7 on five computers, I encountered only one serious glitch. The backup function simply didn't work on one computer. The error message was obscure as always, and troubleshooting on Microsoft's Web site provided no solution. I ended up using third-party backup software. Given that regular backups are essential for a home computer, one can only hope that this will be an unusual problem that gets fixed promptly.

Another disappointment is that Windows 7 doesn't seem to improve boot-up times. In my tests, it took slightly longer to get going on Windows 7 than with XP or Vista on the same computer. I don't think this should be a major issue, though - instead of shutting your computer down, use "sleep mode" instead. This function has improved a lot since XP, and most computers take about 10 seconds to wake up.

Perhaps the most exciting thing about Windows 7 is that it's inspiring computer manufacturers to try new things, and reviving old ideas like touch-enabled "tablet" PCs. It's breathing new life into the computer market. It just won't do much for old clunkers.

Frequently Asked Questions:

What is Windows 7? It’s the latest version of Microsoft’s operating-system software. It succeeds Windows Vista, which was introduced in 2007 and has been criticized for sluggish performance and for bugging users with security questions.

When is it available? New PCs with the software start shipping October 22. That’s when Windows 7 will also be available as a shrink-wrapped upgrade in stores or via download at online retailers, although you may preorder now.

What’s the best new feature of Windows 7? Less nagging. Although Windows 7 retains Vista’s security feature that seeks your permission before doing certain tasks, it’s less needy. It alerts you only about the really important stuff, such as allowing a program to change critical settings. And if you prefer Vista’s more pesky approach, you can make Win 7 act the same way.

What else is new? Windows 7 is faster than Vista. Applications and windows should load more quickly -- that is, assuming your PC meets the minimum system requirements. You’ll find dozens of other enhancements, too. For example, a streamlined taskbar at the bottom of the screen does a better job of organizing multiple applications. And Windows Media Player now plays songs in iTunes’ AAC format.

I’ve heard that Windows 7 is missing some applications that Vista has. True? Yes. A few utilities for managing e-mail and editing photos and movies are missing, including Windows Mail, Windows Photo Gallery and Windows Movie Maker. But these programs weren’t that great in the first place, and most users won’t miss them. (For example, the free Google Picasa is a better photo organizer-editor than Photo Gallery.) You can, however, download the missing apps free at Microsoft’s Windows Live site (www.download.live.com).

What will an upgrade cost? Windows 7 Home Premium is the best choice for consumer use. An upgrade will cost $120, but look for Microsoft to offer promotional discounts near launch time. And if you’re planning to upgrade more than one computer, there’s a money-saving Windows 7 “family pack” ($150) that lets you install one copy on up to three PCs. Other retail versions of the Windows 7 upgrade include the business-oriented Professional ($200) and Ultimate ($220), an everything-but-the-kitchen-sink edition that’s targeted at tech nerds.

I use Windows Vista. Should I upgrade? It depends. Do you find Vista too sluggish? Do its endless security questions make you want to tear your hair out? If so, a Windows 7 upgrade may be worth it, particularly if you plan to keep your PC for a few more years.

I use Windows XP. Should I upgrade? Only if you know what you’re doing. You’ll need to erase and reformat your hard drive before installing Windows 7. And once Win 7 is up and running, you’ll have to reinstall all of your programs and files. This is a job for propeller heads with a weekend to kill. Our advice: Stick with XP until you buy a new PC, which will come with Windows 7 preinstalled.

How do I know whether my PC is powerful enough to run Windows 7? In general, if your computer runs Vista, it can run Windows 7. But things aren’t as clear-cut for XP users. To diagnose your PC’s readiness for Windows 7, download and run Microsoft’s Upgrade Advisor. (Go to www.microsoft.com/windows/windows-7/get/upgrade-advisor.aspx.) This free utility scans your computer and lets you know what changes, if any, are needed.