PC booting problems

[lazypanda]

Hi guys,

I am having a bit of trouble figuring this one out. I am running a PC with the following setup:

Mobo: H55M-E33
HDD: 1 HDD, 1TB Caviar black
1 DVD-ROM burner
PSU: Corsair 600cx
GPU: EVGA GeForce 260 SP216
Memory: 2x2 GB Ripjaw F3-12800
Case: Antec Three Hundred

Now I wrapped it up and booted it up, but it won't boot far (the CPU and GPU fans turn on at max speed, but nothing happens, CPU LED indicator is on indicating that it is on. No signal to monitor from GPU or onboard graphics...).

I've tried many things: power draining, checking memories (switched them with some OCZ), unplugging components one by one, switching PSU.... then I remove the GPU and it boots fine (with monitor plugged to onboard graphic card). That's really odd. So I switched this card with one from my other PC, a GeForce 460. It boots fine. Suspecting I might have somehow blown up my ol 260 I plugged it into another PC and it boots fine. Now I can't figure out why the 260 won't play nice. Does anyone have any idea as to what is wrong?