By Stephen H. Wildstrom Should you upgrade your current computer to Windows XP? There's no question that moving to XP is desirable, but whether it's practical, or even possible without buying a new computer, depends on what you're starting from.
The minimum hardware requirements for an upgrade are steep, though essentially the same as for Windows 2000. Microsoft recommends a 300 MHz Pentium-class processor, 128 MB of RAM, and 1.5 GB of free hard-drive space. I wouldn't bother with anything much slower than a 700 MHz Celeron, and while 128 MB of RAM will work, 256 MB is a lot better. If you have a high-speed Internet connection, you can give your computer a comprehensive readiness check by downloading the 50 MB Upgrade Advisor from Microsoft.
Another word of caution: You're going to need a separate copy of Windows XP for every computer you want to upgrade. Officially, this has always been a requirement of Microsoft's End User Licensing Agreement, but the company had no way to enforce it. During installation, XP generates a unique code based on your hardware configuration and sends that code to Microsoft to activate the installation. If you try to use the same copy of XP on a second machine, activation will fail, though Microsoft will offer to sell you a second license at a not terribly generous 10% discount off the $100 upgrade price, or about $90 for the home version.
ROUTINE APPROVAL. Contrary to some reports, the configuration information itself isn't transmitted to Microsoft, and most hardware changes will not invalidate your activation. If you make major changes, such as replacing the disk drive, you may need a new activation code, but Microsoft says such requests will routinely be granted. Experience with the somewhat similar registration procedure for Office suggests this is indeed the case.
The easiest upgrade to Windows XP will be from Windows 2000, which actually shares a great deal of code with XP. In general, any software or hardware that runs under 2000 will work under XP, so you're unlikely to encounter compatibility issues. (Utilities, such as antivirus software, and CD-burning software are the products most likely to need upgrading when you move to the new operating system.)
The problem is that an upgrade from 2000 also offers the smallest reward. You'll get some definite advantages on laptops, especially those running on wireless networks, and in text quality on flat-panel displays, but 2000 users are already enjoying the benefits of a modern, stable operating system.
PAINLESS PATH. Windows Millennium Edition (Me) offers the best combination of relative ease of upgrading and a big payoff for the effort. Since Me has been shipping for only about a year, it's probably running on hardware that's ready for XP, though a memory upgrade may be needed to get acceptable performance. Me was actually developed with upgradability to XP in mind, so the process is straightforward. And because Me is both buggy and short on important features such as network support, upgrading to XP is especially attractive.
One problem you may have after upgrading from Me, or any Windows version other than 2000, is how to find your data files once you're finished. See my column of Aug. 30 on BW Online, "XP Tips: Where Are My Files?", for information on coping with "lost" files.
Upgrading from Windows 98 is more challenging. Microsoft recommends it only for computers purchased since the begining of 2000, and I think that's good advice. If you have an older computer that meets the hardware requirements, you can give it a try. But the more elderly your machine, the lower your chance of success.
HOPELESS CASE. Fortunately, XP installations generally fail gracefully, letting you revert to the prior operating system without much trouble. Running the Update Advisor could save you $100 bucks on the upgrade software since even if your installation fails, you probably won't be able to return the software once you buy it.
If you're still running Windows 95, don't even think about upgrading. For one thing, unless you for some reason installed 95 on a relatively new machine, you just won't have the horsepower. And Microsoft doesn't support upgrades from 95, so you would have to buy the $199 "full" version. In short, you're a lot better off buying a new computer. Wildstrom is Technology & You columnist for BusinessWeek. Follow his Flash Product Reviews, only on BW Online