Microsoft has created two classifications to help ascertain if your computer is capable of running Windows Vista: Vista Capable and Vista Premium Ready.

Vista Capable pc's need to have :-

- a minimum 800 Mhz CPU,

-512MB of system memory,

-a 20GB hard drive with at least 15GB of free space, and

-a DirectX 9 class graphics card.

A computer that meets these requirements will be able to run all versions of Windows Vista but you may not have access to the transparencies, glass effects and other special features of the new Windows Aero user interface without upgrading your graphics hardware. Since most stores will be selling the DVD version of Windows Vista, it's also advisable to have a DVD-ROM drive installed, although Microsoft state that a CD-ROM version will be available.

Vista Premium Ready pc's will require at least:-

a 1Ghz CPU,

-1GB of system memory,

-a 40GB hard drive with at least 15GB of free space, and

-an Aero-compatible graphics card which supports the new Windows Display Driver Model with at least 128mb of onboard memory.

A computer that meets these requirements will be able to take advantage of the "high end" features of Windows Vista and generally make for a more pleasant experience with transparencies, window animations, and other eye candy.

Microsoft offer the Windows Vista Upgrade Advisor from their website to help determine if your pc is capable of running the various versions of Vista. This utility will only work on a pc running Windows XP or Windows Vista.

These are the "official" minimum requirements, but let's get real for a moment about what hardware you are really going to need to have a satisfying experience using Windows Vista.

I've upgraded literally thousands of computers over the last 3 years, and I couldn't recommend Windows Vista to anyone with a pc running a CPU slower than 1GHz. With a CPU this slow, it's very likely that the maximum amount of memory your pc can handle is going to be 1GB (especially with notebooks). My recommendation is to stick with Windows XP and upgrade to at least 1GB of system memory and enjoy the experience, or look at buying a new computer with Vista pre-installed.

If your PC has at least a 1Ghz CPU then by all means install Windows Vista, but don't mess around with recommended 512mb of RAM. Consider 1GB of RAM as the absolute minimum, and 2GB as the sweet spot. If you're a power user, then I recommend you seriously consider 4GB of installed RAM as a target for the maximum experience, but only if you have a modern CPU (Core Duo 1.8Ghz equivalent or higher) and graphics card (256mb on-board ram or higher).

With the arrival of Windows Vista some say that Microsoft has caught up to, or even exceeded Apple in the user interface experience department, but the hardware requirements are certainly steep. As with Windows XP and most other windows-based operating systems, installing a good amount of system memory is going to give you a pleasant experience and ultimately extend the useful life of your computer.