XP SP3: STOP 0x0000007E (0xC000001D) (solved)
Update: If you arrived here, looking for a solution to a blue screen problem that started to occur on Feb 12th, 2010 - this is a different kind of problem. The solution to that can be found here: Heise Online (English). Basically, it is a side-effect of a Microsoft update (MS10-015) that triggers a flaw in an already present bootkit malware, which then leads to the blue screen of death problem.
From time to time (i. e. every workday ;-)) I still use Windows XP. Recently I kept getting complaints about the system partition being too full. I guess on all operating systems this can have all kinds of funny (or disastrous) effects, so I tried to clean up a little. Apart from the usual suspects (temporary internet files, some huge downloads on the desktop and the like) I noticed that there were literally dozens of $NtUninstall...$ folders containing the setup/uninstall files for a lot of updates that had accumulated over time.
I realized that those could be deleted, however I prefer having a "clean" system, so I went for Service Pack 3 first which should include all the individual patches anyway.
The SP3 network install package first complained about the RDP 6.0 MUI Pack (KB925877) being incompatible with SP3 and that I had to remove it first. Doing so via the Control Panel did not work for some reason: It disappeared from the list, however the SP3 setup still complained. I had to manually delete the registry key pointing to it (HLKM/Software/Microsoft/WindowsNT/CurrentVersion/Hotfix/KB925877) before the SP3 setup would start.
After a while it reported a successfully finished installation and asked for a reboot. So I did.... After the POST I got a quick glance at the XP boot screen which was very quickly replaced with a blue screen of death (official: "STOP error") with these details:
An attempt was made to execute to non-executable memory ... STOP: 0x000000FC (0xBA5038E8, 0xBE903964, 0xBA503848, 0x00000001) ...
I looked at my BIOS settings and found the "XD Technology" option set to "on". According to Intel's support glossary this is the "Execute Disable" feature, so I tried again having it switched off. This just replaced the error codes, the BSOD remained:
... STOP: 0x0000007E (0xC000001D, 0xF78DE8EA, 0xF78DE7F4, 0xF78DE4F0) ...
Neither Safe Mode nor regular boot succeeded. Using a different machine I came across some other people with the same problem. This forum entry gave me the necessary clue - probably one of the next things I would have tried anyway: It's a USB driver problem. I removed all USB peripherals - good thing to have a PS/2 keyboard lying around and that "legacy" port on your mainboard - and Windows immediately booted normally. I did not try to reattach the USB devices, but went right to the device manager and removed everything in the USB category. Even without another reboot I just let it then search modified hardware, having it re-detect all the stuff I had removed a minute before. One more reboot, with everything attached an everything is back to normal. Now I can finally delete the superfluous files for which I started this whole odyssey...