Need help with boot

Hi all i'm having a problem with another pc here i bought last week a gtx 570 i was using before a gtx 260 so yesterday i purchase a new psu (corsair gs600) for another pc to install the gtx 260 there but now after the pc gets to the desktop it works for a while and after 1-2 min the signal of the video is lost but the pc is still on.

So today i boot in safe mode to do a backup of all the files (in safe mode there is no problem at all) reinstall windowns 7 and the problem still is present i try to put the old gpu back a geforce 9600gso and with that the pc boots but i cant see anything in the monitor is just looking for the video signal with the gtx 260 most of the times gets to the desktop the screen blinks and the video image is gone if i still the nvidia drivers in safe mode after a while in the desktop instead of the screen turning black it display a the typical blue screen and the pc just reboot

Could this be a problem of the new psu?

The rest of the pc is

Core 2 duo
2gb ram
Intel DG41RQ

Thanks