Jan 30, 2010
Ordered a new PC which came in yesterday. Played on it for about 16 hours then did a windows update before going to bed. Comp failed on the restart and would shut off after about 2 seconds. Now it will just turn on and off on its own. On for 2-3 seconds off... on again by itself then off etc.. I've checked all the cables unplugged/plugged back in, moved ram. When I took the mothoboard battery out to reset the CMOS it booted up again normally and worked. I then restarted just to make sure it wasn't a fluke and it failed on the restart again and is now doing the same problem on/off every 2-3 seconds.
I got this computer from

CPU: Intel(R) CoreT i7-860 2.80 GHz 8M L2 Cache
MOTHERBOARD: [CrossFireX] GigaByte GA-P55A-UD3 Intel P55 Chipset DDR3 ATX Mainboard w/ 7.1 HD Audio, GbLAN, USB3.0, 2 x SATA-III RAID, 2 Gen2 PCIe, 2 PCIe X1 & 3 PCI
POWERSUPPLY: 700 Watts Power Supplies
VIDEO: NVIDIA GeForce GTX 285 1GB 16X PCI Express


Neither is likely to fix your problem, as it is rebooting before BIOS it is a hardware problem. I know I have the same issue. I managed to fix one PC with this problem by disconnecting everything and cleaning each part, some people have associated this problem with dust buildup.

Hope that helps.