PC resets after upgrade to dual core CPU?

[Draeger]

My brother has bought a new mobo and dual core Pentium CPU.

He's built it all up in a new case and stuck his current hard drive which was running on a different mobo with a single core P4 CPU.

Everything appears to be installed in the correct way, but when the PC gets past the POST screen, its resetting and going to the "How do you want to start Windows?" screen, Normal/Safe mode etc.

Any ideas?. I suggested it may well be because he's trying to boot up a hard drive which was previously running a single core CPU on a different mobo, but I'm not sure if that has any bearing on the problem?.

Apologies for not posting the exact spec/models of the new mobo and CPU, I'll get back to him and post the info ASAP.

Thanks in advance for any advice.

 

[Draeger]

Cheers guys, exactly what I was thinking.

He's just sent me a text saying he's trying a freshly reformatted HD rather than his current one. At the moment he's installing XP on it and it seems to be going ok so I reckon that was probably the problem.