Desktop Failing Its Boot Sequence

I am running Windows XP (SP2) on an eMachines T2080 desktop. All Windows security patches and other OS updates are current. McAfee virus scan is run weekly, as is SpyBot S&D and AVG/Ewido. I am running a GeForce FX 5200 graphics card with up-to-date drivers

The problem is, while using this computer, i had a hung-up process that was slowing things down. After doing CNTL-ALT-DEL to see the process list, i accidentally shut down the explorer process, thinking it was a hung-up internet explorer. Naturally, the computer shut down, but ever since, it does not seem to want to boot appropriately. From a cold power-up, it will go through the "Windows" logo screen with the blue scrolling bar for about 10 seconds, then the screen goes black and stays black for about a minute. Rather than coming to the light blue screen where the user-id's live, the system instantaneously flashes a "blue screen" (with some white characters on the screen), however, it's so fast that I can't read it, nor can I get a screen shot of it. Once that blue screen flashes, it goes back and tries to boot again, only it gives me the options of safe mode, start windows normally, start from last known good configuration, etc. I can boot up just fine in safe mode, but the blue screen phenomenon happens for all the other options. I have tried a system restore to a previous day, and that doesn't work either.

any ideas on how to proceed, short of an OS reinstall / repair. I have seen some suggestions for CMOS battery replacement,I can copy any utility files I need just fine while in safe mode, but I'd like to try and do additional troubleshooting