OK, so an update. I took the rig to the shop and the dignosis is a fucked mobo and power supply. It seems half the capacitors were shot and I just didn't notice it (I was trying to compare normal capacitors to bad ones, but all the ones I was comparing to each other WERE the bad ones).

Thanks for all the help guys. You saved me a lot of time dicking around with the store owner. We were able to get right down to the prob and I should have my PC back with new parts by Tuesday. I'm out $180, but it's better than having to buy a whole new system...