Since you all got obsessed with my PSU here is screenshot of it's front label:
He had the same PSU for a GTX 570 and he couldn't start the PC.
In this post the guy with the best answer says:
Total Power Supply Wattage is NOT the crucial factor in power supply selection!
Total Combined Continuous Power/Current Available on the +12V Rail(s) @ 45°C to 50°C ambient temperature, is the most important factor.
What exactly is that?Can you tell me anything more by the label cause I don't know much about the specs (quite obvious since I bought this PSU).