Customers who have purchased an HP Pavilion or Digital Entertainment Center PC, or a Compaq Pavilion PC -- all desktop models only -- on or after October 26, with Windows XP pre-installed, will be eligible for upgrade kits for corresponding editions of Windows Vista next month, HP announced this morning

The upgrade plan addresses the "coupon" problem that PC vendors are facing this season: having to sell computers to customers with the promise of their being able to run a "full Vista experience" they can't yet see for themselves.

HP's Web site this morning states that customers with proof of purchase of their systems, plus certificates of authenticity for their Windows XP editions, will be able to use the company's "Upgrade Redemption" privileges for downloading upgrade kits. XP Professional Edition customers will be able to upgrade to Vista Business, and Media Center Edition customers may upgrade to Vista Premium.

Meanwhile, XP Home Edition customers can upgrade to Vista Home Basic, which, as some customers will discover, doesn't exactly provide the "full Vista experience," including the 3D-rendered front end with alpha-transparent window frames. The discovery of this fact could lead to our first indication of whether general customers sincerely find this omission of any relevance. If not, it could be bad news for Microsoft, which all this year has pushed the Aero front-end as one raison d'etre for Vista.

Notebook computer owners do not appear to be eligible at present, for reasons HP has not specified.

In its announcement this morning, HP said it was willing to provide some limited help to that end. "HP...is prepared to help address common issues customers face in their transition to Windows Vista in real time through self-paced classes," the announcement reads. "When customers call HP for help, they may be offered an impromptu class on that issue at no charge. The class would be followed by a live question and answer session with a tech support agent. HP has successfully used these classes in the past to respond to virus outbreaks."

Hopefully Microsoft is willing to overlook HP's comparison of the upgrade process to a virus fix.

Today's announcement comes in advance of what was touted last night by HP and Microsoft, in an alert to the media, as a major joint announcement by the two companies to come later this evening. Chances are likely that this announcement concerns Vista in some regard, and is probably more substantive than the availability of Vista upgrade kits.

Last March, a New York Times investigation revealed that it was HP that had asked Microsoft to delay the consumer release of Windows Vista past the original target date of August, though for reasons not even the Times could ascertain. HP later verified that it was in discussions with Microsoft over Vista release dates. Today's conference could conceivably be with regard to whatever it was that mandated HP's request for a delay.

If such is the case, the heading many observers might use to categorize this conference could be, "This Had Better Be Good."