The problem is that HP, and possibly other OEMs, deploy the same image to Intel-based desktops that they do to AMD-based desktops. It also appears that this is unique to their desktop image, and any HP AMD-based laptops are unaffected by the problem. Because the image for both Intel and AMD is the same all have the intelppm.sys driver installed and running. That driver provides power management on Intel-based computers. On an AMD-based computer, amdk8.sys provides the same functionality. 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.