SLI problem or Windows?

I just build a brand new PC
AMD athlon 64 FX 939 Processor FX 60 Dual Core 64FX
ASUS A8n32-SLI Deluxe
Antec P180B
Seagate 400GB
Dual NEC DVD double layer DVD+-CD RW
PNY nVidia GeForce 7600GT 256 mb GDDR3
EVGA e-GeForce 7600GT GDDR3 256MB
Microsoft Windows Media Center

I first booted up with ONE PNY nVidia GeForce 7600GT card. All worked fine for a day or so. Then I added my second EVGA e-GeForce 7600GT, enable SLI in the software booted up and fine. Then added a Netgear wireless G NIC card booted and locked up during the Windows boot. Couldn't restore, nothing. Decided to re-format hard drive and reload everything from scratch WITHOUT Netgear card. Booted 5 times fine and now locked up at Windows again. Do you think it is my SLI and dual GeForce cards? I loaded the nVidia windows drivers should I have loaded the Windows x64 drivers? CPU Temp 52C/125.5F, MB 49C/122F is heat a problem? I haven't added my Thermaltake Big Water SE 12cm liquid cool.
There are not any additional power connectors on the 7600's. I am new to this and at my wits end.

Yea, that is what I was thinking. I just don't know what else to look at. I do not know where to look to see in the Windows boot process what is hanging up. I think it is a software problem.