Problem: BSOD and a long list of technical error with APCI.sys on the end..when you boot on safemode the computer hangs on MUP.sys
there are lot of possible errors (hardware and software alike)but in my case a corrupted driver system,
here is what fixed my problem:
1. boot on xp installation disc (make sure to set bios to boot on cd/dvd)
2. choose repair console (pressing r after the disc installation boots completely)
3. choose what xp installation you want to repair (normally just press 1) leave or press enter if you don't have a password on the password part.
4. type chkdsk /p /r (it will take for a while to perform, mine took 15 minutes- indicating a lot errors on my system files)
5. type exit on the command prompt after the operation.
