No Signal

[Kt3mplar]

For some reason, anytime I try to boot my brand new self-built computer, I don't get a signal.
I have two theories, it's either the motherboard or the video card. I don't think it's the video card. They're both OEM and pretty expensive for a man on a budget, and it would be a shame to have to replace either of them.
I tried seating the card in the slave SLI slot, but that didn't help. I think it's the motherboard, because the CMOS has been acting funky, too. Any suggestions?\
Case:Xion II
PSU: 520W Apevia Aspire 12V ATX
MB: Asus A8N-SLI- OEM
GPU: Nvidia Geforce 7600GS
RAM: 1GB Geil PC3200
HD: Seagate Barracuda 7200.10 320GB SATA
CPU: AMD Athlon 64 3800+ 2.4 GHz

 

[tifc8lraz]

What is the amp rating on the +12V Rail of your power supply?

 

[Kt3mplar]

+12V1 is 16 amps.
+12V2 is 18 amps.
-12V is .8 amps.
Don't think that's it. System worked fine (arguably) until just very recently, when I tried to reinstall XP. I've got another thread on the XP installation error.