ASRock Z68 Extreme3 Gen3 with Ivy

Hey i have built a pc and just found out why it wasnt working, its because i got a ivy bridge cpu with a ASRock Z68 Extreme3 Gen3. Can anyone help with this. the problem is that when the psu is connected to the 8-pin connecter it starts up then shuts down,then i disconnected it so no power was going to the cpu and it worked fine no shuting down or anything exept the cpu wasnt powered so any please helpp??