Asus i5 - Seemingly Random Shutdown

All, I recently built a system with the following components, running XP 64-bit

Asus P7 1156 chipset
Intel i5
Corsair 750
8800GTS

The operating system load went well, I updated the drivers for my components, and installed the windows updates.

When running the ASUS auto-tuning the system occasionally just shutdown, and rebooted and picked up from there, it was as if it were supposed to do that, however, since then the PC has shut down in the same fashion, and restarted at seemingly random times

There is this Asus express gate that says it's not installed on startup, but I'm not sure I really want to install it, since the file is like 600 MB, and looking at what it does, I don't really want it

The problem is I am not getting any information after the restart as to what is responsible for the random shutdown, is there any logs I can look into?

What steps can I take to debug this problem?

I can't rule out a hardware problem, but my CPU temps are not a factor, they are consistently cool when the shutdowns occur. The video card has undergone some stress in another computer, but seems to be working fine, I was playing BIOShock on Ultra settings, and it all worked great

My guess is that there is a software issue, since the shutdowns don't seem to be correlated to system stress.

Thanks!