Computer won't boot

My problems seemed to start last night. I had a "USB malfunction" which caused me to be unable to move my mouse. I switched to another port and all was fine. Then this morning I go to turn on my computer and it boots for a second, then it seems to turn on and off really quick. I can tell from my LED fans, they flicker on and off. I've tested different PSUs in this machine, none worked. Tested my PSU in another machine, it worked. I tried plugging it into another jack, no dice. I unplugged everything besides the CPU, RAM, video card and it still did the same thing. I've come to the conclusion that it must be the motherboard or the processor, but it seems like it would have to be the motherboard because the processor wouldn't cause the flickering. Did I leave anything out? I have a hard time believing that it would just randomly stop working on me. Any suggestions?

Look for physical defects on the motherboard... like caps that broke off or leaking... funny smell or burnt smell... etc... any abnormality??

Also, have you entered the Bios to reset it to default settings to see if it boots?

I can't get into the BIOS but I did reset the jumper and it still did the same thing. I didn't notice a smell or any superficial marks, but I'll look again. It seems like the motherboard just died. :( I sent an email to Chaintech support, is that how you get an RMA? How long is their warrenty usually? I've never done it with them and their site kind of sucks. I didn't see an RMA section. If I can't get an RMA should I buy another s754 motherboard or move up to s939 and sell my CPU/9800 Pro? In the first case, what motherboard would be best and in the other what is a good midrange overclockable 939 setup and a pretty good video card($250ish)?

Thanks for the reply.