Computer won't start (no image but powers up) (details exact in message)

[GrahznyEggywegg]

Hi, my PC doesn't display any image, when turned on all the fans start and I hear a vague revving noise (assume this is CPU?) which keeps revving up then quieting down, as it revs up full the HDD light flashes once, and it repeats this until if revs up again. It went dead a few weeks ago and today I turned it on and it worked for a few hours before going dead again, repeating the process exactly! I'm not sure what the problem is, thought it was motherboard or cpu, but why would it be ok for a few hours every now and again? Can somebody help? Many thanks, Dan

 

[Brett928S2]

Hi

Specs ?

All the best Brett