System not working with gfx card

[smltngs]

I have a corsair vx450w PSU and nvidia gtx 560 GPU.
My system was working smoothly till I installed a new CM Hyper 212 Evo cooler for my CPU(amd phenom IIX4 965BE).
Now whenever I press power button, the fans are rotating for half second and the sys is not powering up.
Without the GPU connected, sys is working fine with the onboard GPU.
Please help me.

update: I tried my old card 8600gt with my system. Its working fine.

update: connected my PSU to another mobo and checked both 560 and 8600gt cards with it.
only 8600gt is working even with that mobo. so does this confirm my gpu is the culprit?

 

[d6bmg]

Test your GPU with other PSUs if possible or test it in your friend's rig.
Could be problem with PSU or GPU.

 

[gameranand]

Either your PSU is not handling GPU or your GPU is the culprit. Do as d6bmg says.