Get It?

To all the stickers that encrust the average PC -- the ones advertising their processors, graphics cards and potential to inflict repetitive-stress injury -- you can add one more. It's a version of the familiar Windows XP logo that proclaims the computer "Vista Capable."

This emblem is supposed to answer what should be Topic A for most computer shoppers: Now that Microsoft's Windows Vista is less than three months from arriving in stores, can a new XP machine make the move to Vista when it arrives?

That word "Capable" promises a straightforward, reassuring answer of "yes." But in practice, it can mean anything from "absolutely" to "maybe" to "not really."

Even as Microsoft is revving up its Vista marketing campaign (last week, it announced a set of discounted upgrade offers for buyers of new PCs), customers can often only guess which computers will give them the advertised Vista experience.

Part of this mess stems from Microsoft's decision to develop five versions of Vista: Home Basic, Home Premium, Business, Enterprise and Ultimate. (Customers in developing countries will have a sixth option, the stripped-down Starter Edition.)

Even though most home users will only have to pick between the Basic and Premium flavors, those two alone have significantly different features and requirements.

Vista Home Basic, a $100 upgrade from Windows XP, will include the same security and file-management upgrades as other Vista editions. But it leaves out most of the features Microsoft has been talking up in Vista: its 3-D Aero Glass user interface, "Media Center" software to turn the computer into a home theater and DVD-burning tools.

Those and other features require buying Vista Home Premium. It costs more, $159 when upgrading from XP, and demands a great deal more hardware.

Here's where those little stickers lead you astray: Microsoft defines a "Vista Capable" computer as one that can run Vista Home -- not Premium. And these entry-level requirements are so lenient that most PCs sold in the few years can meet them.

To get the Vista features you'll probably hear the most about, you'll need a machine satisfying Microsoft's "Premium Ready" requirements ( http://www.microsoft.com/windowsvista/getready/capable.mspx ). And there is no standard logo advertising this higher level of compatibility, only such jargon-soaked fine print as Microsoft's description of an Aero Glass-compatible graphics card: "Support for DirectX 9 graphics with a WDDM driver, 128 MB of graphics memory (minimum), Pixel Shader 2.0 and 32 bits per pixel."

That means that the manufacturers will have to tell you which models meet the Premium spec. And most of them are botching the job.

At Dell's Web site, individual models' listings don't indicate their Premium readiness, or even link to the page elsewhere on the company's site that does spell out which PCs meet that higher requirement. Hewlett-Packard repeats that mistake on its own site, while Gateway's site implies that the company doesn't sell any Premium ready computers.

Toshiba, despite having one of the worst Web sites of any computer manufacturer, at least provides an obvious "Get Windows Vista Premium Ready" link to steer you to the right laptops.

The situation in stores is even worse, to judge from visits to a Best Buy and Circuit City in Baileys Crossroads yesterday. Most computers on display carried a "Vista Capable" sticker, but finding any evidence of Premium compatibility required careful inspection.

For every manufacturer's reasonably prominent "Premium Ready" label-- for instance, Sony's -- there were others in small type, covered by inventory stickers, or already rubbed away by the palms of shoppers trying out laptop keyboards.

You'd have to ask a salesperson for help -- and hope he or she had memorized which computers were at which level of Vista readiness.

This isn't the first time customers have had to puzzle through complicated technical decisions in the face of misleading marketing. "HD-ready" high-definition TVs, thanks to their lack of digital tuners, can't receive any actual HD broadcasts; the "PlaysForSure" label on many digital-music devices doesn't stop them from failing to play some Windows Media downloads.

But when Microsoft and its partners have so much at stake -- they're only looking at their biggest transition since the arrival of Windows XP -- you'd think they'd work harder to steer customers straight.

Living with technology, or trying to? E-mail Rob Pegoraro atrobp@washpost.com.