Windows Help Please: New Comp Crashing :( CS:S related?

Hey guys whats up. Im a total software nerd, but Im having a prob maybe some of you more knowledgeable will know. I just built a new computer this last week and after i got everything up and running, i played source a few times, browsed the internet, and ran some other applications and everything ran just fine.

Now, when i try to play CS:Source my computer crashes right when it gets to the "Sending Client Info" part of the loading. And ill have to restart my computer . Im running windows XP Pro with service pack 2, everything running off my sata raptor.

Heres a list of the parts im running on the computer.

DFI NF4 SLI dr Mobo
74 gb raptor
amd 64 3500+
2 BFG 6800 Ultra Ocs
1 gb Kingston Hyper x

Any help with this i would greatly appreciate, seems kinda like a software/install issue, but now im kinda starting to think hardware maybe cuz it stalls always at this one loading part of CS:S??

Thanx

-B-