So, the power went off in the office. I turned on the computer (running XP SP3) and it ran very very slowly. I booted into Safe mode. The computer ran very slowly, but I was able to schedule a ChkDsk.
I rebooted. Chkdsk ran, The Windows logo came up and went to a black screen with an arrow. The hard drive light flickers, but Windows won't load any further.
Went into Safe mode. The OS stopped loading at aswRvrt.sys.
Checked around the Internet, which is how I ended up on this forum. My situtation seems to be a fairly common problem with older versions of Windows + Avast.
I loaded the Recovery console, ran another ChkDsk, which didn't find anything.
I did a search in the System32 folder for all drivers starting with ASW.
I checked that each one of them was used by Avast, and I disabled them via the Recovery Console.
Windows still won't load...same black screen.
Windows in Safe Mode stops at MUP.sys.
I am stumped. I really really don't want to reinstall Windows, but I can't think of anything else to do to get rid of Avast and get my system running again.