Cpu problem?

[cooler_power]

pc specs:
cpu: intel e8400 3GHz (never overclocked)
ram: OCZ 2x2GB (never overclocked)
gpu: gigabyte nvidia 8600GT
motherboard: i changed the asus mobo with an Asrock x48TurboTwins (Brand New)
psu: i changed the old psu with a cooler master extreme power 650w (Brand New)

when i start the pc nothing shows up on the monitor (no signal). I tried 2 different monitors and cables and i also changed the graphics card, psu and motherboard and ram and still had the problem. I then removed the cpu and put an E6600 and the pc was ok but when i put back the E8400 the pc booted fine and my monitor showed the bios and windows but only for about 2 minutes then the pc restarted by itself and i had the same problem with monitor not getting signal from the pc. Do you think that the problem is the E8400?

thank you in advance

 

[raiyus13]

Is there enough room inside of your chassis? your CPU might be overheating. check the thermal paste status,also clean the heatsink.

 

[cooler_power]

Is there enough room inside of your chassis? your CPU might be overheating. check the thermal paste status,also clean the heatsink.

I checked the cpu temparature in the bios and it was 43C and 38C the mobo so i don't think its an overheating problem. The heatsink is clean like new and for thermal paste i used the AC MX-2

 

[raiyus13]

Ye, temps are quite normal, can you just check your psu,it can be the culprit.

 

[sarwar_r87]

just to be use, check if your current bios supports the CPU

it says you need bios rev P1.20 to support e8400 if its E0 stepping.....if ur unsure which stepping your on, update the bios nonetheless if its not updated

http://www.asrock.com/mb/cpu.asp?Model=X48TurboTwins-WiFi