Okay first off I just found out that I had a RAM issue (I had two 2GB sticks of RAM, one stick went bad, so I'm running with a single 2GB stick of RAM in the computer with the issue right now). At first I thought it was a PSU issue, so I was swapping out PSUs from another system to test the problem (which is how the issue about the RAM got solved). When I plugged my PSU into the other system (as well as my hard drive), it turned off right before Windows started. I figured this was due to the fact that the system I was trying this one only had 1GB of RAM in it.
Anyway, I have my hard drive back in my computer with the 2GB stick of RAM that works (the system won't post or even give an error code with the other 2GB stick in there) and it's doing the same thing before loading Windows; it's rebooting. I even tried going into the Windows System Restore thing and it works for a while, then the computer just reboots again. Could this be due to the fact that I'm only running with 2GB of RAM right now, or does this sound like completely unrelated problem (i.e. somethings wrong with Windows causing the system to reboot). Any help or suggestions would be apprecited. Thanks.