computer starting then shuting down?

[razer121]

ive just been given a "Broken" pc, everything in it works except the motherboard and cpu, when i boot it the computer will turn on then straight back of however! if i remove the 4 pin power plug the computer will switch on and stay on but not display anything, also if i remove the cpu it will also switch on and stay on but display nothing (didnt exspect it to when i removed the cpu) so im thinking its the cpu, is there any other tests i can do before i dispose of the cpu and replace?

[GoNz0]

could be the mobo, the rampage2 extreme does that, its either a dead mobo or bios, i got out of it by removing the battery and resetting the bios, 1st board was dead, 2nd lived.

[razer121]

ok, its a shame it would be sellable lol, the cpu is a 3.2 soclet 775 p4, going to go with the motherboard shorting out somehow and flog the bits on as spares or repair, ive no other way of testing unfortunatly