I can't update my machine to service pack 2. I can update and run SP1 and install every hotfix, but if I update my system to SP2 all I get when the machine goes to reboot is an endless BSOD loop. Safe mode doesn't work, nothing. I've removed everything from my system except memory and video. Still no joy. I shut down and let it sit for a while and did a cold boot and still no joy, continuous BSOD. Then the only way to fix that is to format and re-install OS. Has anybody else had this problem?

System specs -
ECS P4VXASD2+ w/P4 1.5 GHz
ASUS GeForce2 GTS 64MB video
512MB PC2700 DDR Crucial Memory
30 GB WD HDD
20 GB Maxtor HDD
Toshiba DVD-ROM
TDK DVD/+RW

I've even tried swapping out the nvidia vc for an old ATI Rage and that didn't help after the upgrade to SP2. All Microsoft has to say is that they can't help me without getting the info form the BSOD, and I can't even break or pause screen because the crash just flashes the BSOD for like a nano second (not a nano second, but it's too damn quick to do anything before the system reboots) if you blink while the blue screens up you'd miss it, reboot. SP1 runs stable, my system runs great! But if I go to install SP2 it continuously loops until I kill it. Help? Or should I just leave it alone, what's the advantage to having SP2? Security? I use Zonealarm and AVG 7.0 plus my computer is behind two routers (one a firewall) and a switch.

Any help would be greatly appreciated. Thanks