HELP! System shutoff problem in new build... (urgent)

Hey guys. Here's what's in it (Antec p180b case):

Q6600 w/stock fan
Asus P5N-E SLI mobo
2gb OCZ 6400 ram
evga 8800 gts 320
150gb raptor
2x 500gb samsungs
1 old ide cd-rom

Put it all together last night, minus the cd-rom. Everything boots up nicely, look through bios, reset clock, dont' touch anything else. Let it run for ~1 hour, shut it down go to sleep.

Get up this morning, throw in the old IDE cd-rom drive (don't yet have the dvd burner I'm planning on putting in) to install XP pro. Put this disc in, hit the power button, runs for about 10 seconds and shuts off. I try again, it gets about 3 minutes into the XP setup and does the same thing. Now, I turn to you.

All fans were set on high, both sides of the case are open. I'm not thinking its a heat problem, but I could be wrong? I watched the BIOS temp monitor, and it says that the cpu temp climbs up to 64, at which point it turned off. Could it be a RAM problem? HELP! thanks guys.

btw: i removed the cd-rom and its now just sitting in bios, apparently running fine, but its only been up a few minutes so... why would the cd-rom cause this, if thats in fact what it is? thanks

update: nope, died in bios too