Computer boots sometimes (randomly), and most often doesn't.

[Turtleontea]

My custom pc at first booted everytime (to the bios as no OS), it began with 'cpu fan error', I reapplied thermal paste and mounted the heatsink on, again. It then booted fine for a bit before going dead, power but no output, CPU wasn't doing anything either (no heat). This was to me because of a psu error and most tomshardware threads suggested testing with another psu. I took it out of the case and tested it and reassembled everything (with a new psu), it worked, I immediately reinstalled it but after leaving it for an hour it wouldn't boot again. The cpu was bought working only a few weeks ago, the psu to, as with the case and everything but the motherboard. I found it randomly booted after small tweeks like cableing again with atx 24 pin and the one allocated next to the cpu (4 pin).

I fear this is a motherboard issue. Mine Is the hp m2n68-la motherboard and it seems functional but I don't know if it is. I have a motherboard PCI error card but this shows success I power distribution but only 00 is shown in led (means nothing).

If specs are needed I will give them, but I suspect they are of no use, I know they are all fully compatible and bought working.

HELP!

 

[hang-the-9]

When you say the CPU was bought working, did you get a used one?

Need full system specs, including PSU brand and model and what is new, what is not. How long was the sytem working before it stopped? Was anything overclocked?