I've been searching through the internet for a solution to this grand problem and this seemed like the best place to get information. On to the problem.
I attempted to update the graphics driver for my onboard video card. It's an ATI Radeon 200 Express. I previously had an nVidia 7600gs 512mb pci-e installed but there was a problem with the PCI-E bus so I had to remove it. Before that I had an ATI Radeon X1600 pro. I know there are a lot of graphics cards in there, but I forgot to uninstall display drivers before doing this (a no-no, I'm sure.)
Anyway, I downloaded the new drivers, installed it and it hung for a bit and the installation program went away, but the computer didn't restart after it asked me to. I went to the start menu and restarted it there and it went without a hitch. After it attempted to reboot, the computer now continually reboots after "mup.sys". I've looked all over the place and there were suggestions about removing USB devices, PnP devices, IDE controllers, updating the BIOS, resetting the ESCD, chkdsk /r, and repairing the Windows installation.
I'm pretty sure that it has nothing to do with mup.sys since the boot screen shows it loads, and I've disabled it as well, just to have the system reset again. I don't know where to check the bootlog to see which driver did or did not load after that for me to check, although I'm assuming it does have to do with my graphics card. I cannot get into safe mode, with or without networking, or the command prompt. The "Last Known Good Configuration" also just restarts my computer. I've on occasion seen the flash of the dreaded blue screen, but I haven't been able to make out what my error is before the computer restarts.
What I've done so far:
+ Run chkdsk /r twice. Failed.
+ Reset the ESCD by removing the battery. Failed.
+ Used optimal BIOS settings. Failed. BIOS is the most recent version.
+ Tried 2 other graphics cards in my PCI-E slot: the Radeon x1600 pro; Failed. The nVidia 7600gs; Failed.
+ Followed Microsoft support thread KB307545 to change system registry values. Failed.
The only thing I haven't tried is a repair of the Windows installation via a Windows CD because I have no Windows CD. It's a Compaq that I bought from the store and it didn't come with a restoration CD or anything. I just downloaded a recovery console ISO that allows me to get to the recovery console.
I'm at wit's end. I have my share of experience in fixing all sorts of computer problems, from network problems to staring hours at black and white command prompts and reboots. This one is really pushing my buttons. Any help would be greatly appreciated. If you need any clarification on any events or system hardware/software, feel free to ask. Thank you for your time.