HP had spent considerable time and money setting up new systems that were WDDM (Windows Device Driver Model) compatible. The Vista Capable campaign was meant to assure PC buyers who bought systems prior to Vista's launch that they would be able to upgrade their machines to the new OS when it became available. At that time, many PC manufacturers were not aware of Vista’s resource hungry requirements, Microsoft in its pride went ahead and claimed even the low end PC’s as Vista capable. The Intel 915 graphics chipset is a PC component that boosts a system's ability to display multimedia effects. However, it lacks the necessary features to support Vista's 3-D Aero interface. Emails in the ongoing class-action lawsuit against Microsoft over its Vista Capable campaign have revealed the depth of animosity it caused with Microsoft partners. A set of emails from Richard Walker, senior vice president at HP's consumer PC unit, discuss the decision Microsoft made to downgrade the specification it classes as Vista Capable to include the Windows Device Driver Model (WDDM). The e-mail was dated Feb. 26, 2007 about one month after Vista debuted on the market. The e-mails have been entered into evidence in a class-action lawsuit that accuses Microsoft of deceptive marketing practices. The plaintiffs contend that Microsoft intentionally duped customers by advertising as Vista Capable computers that lacked the horsepower to run all of the operating system's features.

The case hinges on claims that Microsoft knew that so-called Vista Capable PCs would only be able to run the cut down version of Vista, without the Aero interface.

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