This year, walking into the store to purchase a new system has been complicated by releases of Microsoft's Windows Vista and Office 2007 products -- because they are not being shipped yet, except to corporate accounts.

There are a number of features in Vista and Office 2007 that make them enticing; but instead of addressing the features one-by-one, let's simply say that generally, it's better to have the latest releases of software when buying a new computer -- especially operating system software and mission-critical applications, such as Windows and Office. They will be supported longer and help you stay compatible longer with other users.

Computer manufacturers, including Gateway and Hewlett Packard, have teamed up with Microsoft to let you buy a system now with Windows XP -- the current version of Windows -- and get an upgrade to Windows Vista after it is officially released on Jan. 30. But you need to know what you're buying now to understand what you'll be getting later. That way, you'll buy a compatible device and will minimize the amount that you will spend.

To make sure that your system can get an upgrade, you need to look for stickers on the system or text on the box that says "Windows Vista Capable" or "Windows Vista Premium Ready." The main difference is that the latter sticker guarantees the system will run all versions of Windows Vista; the former guarantees compatibility with only the entry level version called Windows Vista Home. If you're interested in running Vista's cool, new interface, called Aero Glass, you'll need more than the entry level version that is signified by the Windows Vista Capable sticker.

Here's where it gets a bit more complicated.

The version of Windows Vista you get in your free upgrade usually depends on the version of Windows XP that comes pre-loaded on the system. If you buy a Gateway at the company's Web site with Windows Media Center, you'll get an upgrade to Vista Home Premium -- the second level of Vista, which includes Aero Glass and Windows Media Center. If you buy a Gateway with Windows XP Professional or Tablet PC Editions, you'll get a free upgrade to Vista Business.

Hewlett Packard will upgrade you to Home Basic (the entry level edition) if you purchase a system now with Windows XP Home Edition. If you buy a Windows Media Center PC, they'll upgrade you to Home Premium. And if you buy a system with Windows XP Pro, you'll get upgraded to Vista Business.

HP says your upgrade comes through coupons you'll find in the box that help you order the CDs for the upgrade at their Web site. But you don't have to open the box to know what you're getting. The upgrade should be listed on the outside. If not, ask your retailer.

Oh, and by the way, the retailers can put their own spins on the upgrade program too.

To keep your sanity through the selection process, consider the sticker the same way that you look at the gas mileage on the sticker of a car on the dealer's lot -- for comparison purposes -- to give you some piece of mind that you know at least the minimum level of Windows Vista that will run on the system you're thinking of buying. I've been carrying a Gateway NX100X laptop with the "Windows Vista Capable" sticker (signifying bare minimum); yet my robust configuration runs like a champ with the most powerful edition of Windows Vista (called Windows Vista Ultimate).

For more detailed information, Microsoft has put together a Web page that includes information on upgrade programs and the differences among the various editions of Windows Vista.