Before you even buy a copy of Vista, your first order of business should be to check your computer against the list of hardware requirements for Windows Vista, as published by Microsoft. Vista, as it turns out, is a serious hogfor memory, speed, disk space, and, above all, graphics-card horsepower. 2004-era computers (and earlier ones) probably aren't up to the challenge.

Turns out there are two degrees of Vista-readiness: the lame one and the real one.

"Vista ready"

A lower-powered computer can run Vista. It may feel slow, and you don't see the Aero Glass look (transparent window edges, taskbar thumbnails, and so on). It does, however, offer all the other Vista security and feature enhancements.

Here's what such a computer requires:

• Processor: 800 megahertz or faster

• Memory: 512 megabytes or more

• Hard-disk space: At least 15 gigabytes free

• Monitor: Super VGA (800 x 600) or higher-resolution

• Graphics card: DirectX 9 support (check the packaging or, for laptops, the manufacturer's Web site)

• DVD drive

"Vista Premium"

You need a beefier machine if you want the full Vista experience:

• Processor: 1 gigahertz or faster

• Memory: 1 gigabyte or more

• Hard-disk space: At least 15 gigabytes free

• Graphics card: Works with DirectX 9, WDDM (Windows Vista Display Driver Model), 128 MB of graphics memory, Pixel Shader 2.0, and 32 bits per pixel. (Again, this may be tough to figure out. A sticker that says "Vista Premium-Ready" is a good sign.)

• DVD-ROM drive, audio output, Internet access

If your computer doesn't meet these requirements, then consider a hardware upgradeespecially a memory upgradebefore you even attempt to install Windows Vista. With memory prices what they are today (read: dirt cheap), you'll thank yourself later for adding as much RAM as you can afford.

Adding more hard disk space is also a reasonably easy and inexpensive upgrade, and there are inexpensive graphics adapters that will handle Vista's visual effects.

The one place where you may be stuck, though, is on the processor issue. The state of the art in processor speeds seems to advance almost weekly, but it's safe to say that a PC running at 800 MHz or less is certifiably geriatric. It may be time to think about passing the old girl on to the kids or donating it to a worthy cause and getting yourself a newer, faster computer. As a bonus, it will come with Windows Vista preinstalled.

The Compatibility Issue

Once you've had a conversation with yourself about your equipment, it's time to investigate the suitability of your existing software and add-on gear for use with Vista.

• Hardware. In general, products released since October 2006 are Vistacompatible, but you should still proceed with caution before using them with Windows Vista. You should by all means check the Web sites of these components' manufacturers in hopes of finding updated driver software.

• Software. Most programs and drivers that work with Windows XP work fine in Windows Vista, but not all. And programs designed for Windows 95, 98, and Me may well cause you problems.

Unless you're that lucky individual who's starting fresh with a brand new PC and software suite, you'd be wise to run the Windows Vista Upgrade Advisor program before you move into Vista World.

If you haven't yet bought Vista, you can download this important program from Microsoft's Web site at http://go.microsoft.com/fwlink/?linkid=60497. It runs only on Windows XP (and, pointlessly, Vista), and it scans your system to produce a report on the Vista compatibility of your hardware and software.

If you do have Vista, insert the Windows Vista DVD. On its welcome screen, click "Check compatibility online," and then download the Windows Vista Upgrade Advisor.

The Upgrade Advisor first offers to download updates from Microsoft's Web site. If you can get online, it's an excellent idea to take it up on this offer. You'll get all the patches, updates, and bug fixes Microsoft has released since the debut of Windows Vista.

Next, the advisor shows you a report that identifies potential problems. Almost everybody finds some incompatibilities reported here, because Microsoft is particularly conservative about which programs will work with Vista.

But if the report lists a serious incompatibility, it's not worth proceeding with the Vista installation until you've updated or uninstalled the offending program.