Windows 7 hanging - system unusable

Hi all,

We have a Maingear gaming system that is hanging after login for 20 to 30 minutes. This doesn't happen in Safe Mode; however we have reinstalled Windows 7 from scratch 4 times and reconfigured the SSD back to RAID 1 (former problem had them in another config). Patriot RAM 12GB passes with flying colors with Memtest 86+. We are at our wits end - tried just about everything other than dropping it off a tall building. We've removed extraneous cards, disabled legacy USB in BIOS, all to no avail. About 1 in 10 times it boots up and stays clean. Otherwise, it's useless and can't be used (just a spinning blue windows symbol).

I thought it was hardware - not so sure now as Safe Mode seems stable.

We have little to no BSOD, fan is running fine. Should we try removing the NVIDIA video card?

This is an i7 970 3.2 GHz 6 core system with an ASUS Sabertooth X58 motherboard, 2 1 TB drives set to RAID 1 mirroring.

The system is back to clean install with only Zone Alarm installed (problem happens without Zone Alarm, too).

We had a short in a USB panel a while back, but Maingear replaced it and it works fine. Might be a red herring, but wondering if the motherboard was damaged.

Any ideas?

Thanks.