"The problem is that HP, and possibly other OEMs, deploy the same image to Intel-based desktops that they do to AMD-based desktops," Johansson said. "Microsoft points out in a Knowledge Base article that installing both drivers on the same computer is an unsupported configuration, putting the blame on the OEM that deploys the image. The article in question was written when the same problem occurred after installing Service Pack 2 for Windows XP." Microsoft unveiled XP SP2 in August 2004.

According to Johansson, only HP desktop models are affected. "It also appears that this is unique to their desktop image, and any HP AMD-based laptops are unaffected by the problem," he said.

As Johansson mentioned, Microsoft has dubbed the practice "unsupported" in KB888372. "We do not support using Sysprep to install an operating system from an image if the image was created by using a computer that has a different processor," said Microsoft. "For example, you cannot create a Sysprep image on a computer that has an Intel processor and deploy the image to a computer that has an AMD processor."

KB888372 instructed users how to modify the Windows registry to disable the errant Intel driver, assuming users could regain control of their PCs long enough to boot into Safe mode.

The company has also listed several other scenarios that OEMs should avoid in another support document.

Microsoft and Hewlett-Packard did not immediately respond to questions Sunday.