I was cleaning up a PC for a customer last night which had Windows XP Home SP 2. I figured I would go shead and download all the Windows security patches to help prevent any future problems. I started with SP3, which downloaded and started installing. I left it to finish overnight; when I checked the PC this morning, it had rebooted but was sitting at the menu to choose whether to load Windows XP or the Recovery Console. I had no keyboard access so I shut off the PC then started it. It started booting Windows, then blue screened, then rebooted. I went into Safe Mode ok, set the recovery options to not reboot after a stop error, rebooted, then was able to see the stop error. A search on stop error 7e and service pack 3 turned up this blog which contained instructions for fixing a problem the same as mine. The blogger talked about PCs having an AMD CPU getting this error after loading SP3. Sure enough, the PC I was working on had an AMD CPU. The solution was to go into the recovery console (luckily, as I mentioend earlier, this was already available via the startup menu), selecting the Windows installation, and typing “disable intelppm” (without the quotes). I received a message that this service had been changed from start to stopped (or something along these lines). I exited the recovery console and was able to boot normally into Windows.
You have to wonder if it is a coincidence that the system file causing the problem on an AMD PC was made by Intel.