Windows boot stuck at loading agp440.sys

Ok, this is a Windows tip, once in a while I still boot Windows 2000, until suddenly it would no longer boot. From booting in Safe Mode I saw that it was stuck loading winnt\system32\drivers\agp440.sys.

This solution probably applies to you if you either (1) recently updated your BIOS, or (2) made some modifications to your BIOS settings, specifically the ACPI ("Advanced Configuration and Power Interface") settings.

As always on the Internet it is very difficult to find the signal through the noise (how many people will find this page, I wonder). Too often the solution suggested for Windows problems is disable/delete/reinstall Windows/run chkdsk, etc., without really identifying the cause.

For this one, if you go down the road: boot from CD -> Recovery Console -> disable agp440, and reboot, you'll only find that at next boot you'll be stuck at the next driver (mup.sys)(so don't bother).

After a BIOS update, either because of the update or because I was fiddling with the settings, I had disabled ACPI, which is what caused the lockup. So to fix it: reboot, hit Del to access your BIOS settings (this may be a different key in your case), find the Power -> ACPI settings, and re-enable. Save settings and reboot...