PC restarts automatically for no real reason

Hi,My pc either does not boot at all despite pressing the power button or if boots once then it goes into a cycle where is restarts itself for no apparent reason what so ever. I have Fedora 14 installed on it and it is the only OS. It has been troubling me for the last 1 month or so, otherwise it was working well and I used to work on my pc for hours on end. There is no virus problem as such. All the other parts have been checked with other pc such as the hard disk, CD Drive, RAM, CPU, power supply and even the monitor. But I am still no where near the real cause as to why it happens. Please guide me. Thanks.

Hi,My pc and the motherboard are both hardly 18 months old. The pc was lying unused for almost a year until I started using it daily a few months back. To me it also looks like that the power supply is the culprit, but when I used the same power supply in another pc it worked well for more than a day. But it is only 230 Watts, is it an issue here? How much a good power supply costs generally? Thanks.

The CMOS battery is just 2 weeks old. I am not a gamer or into designing heavy duty stuff such as animation or graphics. I just do some basic programming and use Linux - Fedora 14, Ubuntu 11.04, Debian etc. I have only 1GB DDR2 RAM but I am ok with it.

Sometimes when it restarts there is American Megatrends screen and there is a message on this screen which goes like...


Warning ! over clock fail

I have never changed anything in the BIOS and I have never even dreamed of over-clocking if this is what this error message means. I do not even know how to overclock. The motherboard is Biostar G31-M7 TE and BIOS is from AMIBIOS ie American Megatrends.

Thanks.