I am going to side with waco on this one and say it is a dying motherboard. Foxcon boards are usually a bad idea for a system like yours, and this situation does have some tell tale signs of bad voltage regulators.
I would say the quickest way to find out what this is, is go to your nearest tech store and buy a PSU. Plug it in. And if you experience the same issues, return it and you know the motherboard is the issue. If it fixes the problem, then you can keep the new PSU.
i went to the nearest tech store but didn't have the money to buy a 320w "biggest they had & not p4 compatible" power supply for $110 waaaay over priced im probaly going to order one off the net, the only old componet in the computer is the power supply, ive been buying parts for quite a while and slowly upgrading from my old hard ware the foxconn mobo and ram is about a month old the first two weeks was crazy talking to foxconn about bios issues "bios showed my cpu as a amd x2", finally they sent me a new bios chip for it for the aggervation ill probally never buy foxconn again! only got it because it was on sale 50% off