This was a doosey! I had a situation today where a user attempted to install Windows XP Service Pack 3. After the reboot they got the blue screen of death with error code 0x000000FC. The pc would not boot into Safe Mode either. They exhaused all of their options then called in for support. Below I'll summarize the steps I took to resolve this issue. You can give this a try if you experience these problems.
- I disabled Data Execution Prevention in the Bios and tried to boot. The BSOD error code changed to 0x0000007E.
- I noticed that when no usb devices are plugged into the pc it will boot. Of course, that's not a good solution but at least points in the right direction. The usb driver is the culprit!
- I Replaced the SP3 versions of windows\system32\drivers\usbehci.sys and windows\system32\drivers\usbport.sys with old (sp2) versions using the Recovery Console.
- I was then able to boot into Windows normally!
This solution worked beautifully on this system and everything is now back to normal. If you're ever in this situation give this solution a try. It may save you a lot of time!