CPU won’t start after installing Call of Duty game

Hi! I was using my computer a while ago and was installing Call of Duty. While the system was copying the files, I left it for a while and when I came back, the CPU is already turned off. When I tried to turn it back on, it doesn’t respond. The only thing I get is the monitor LED light blinking. Please help! I have no idea what happened. Here are the specs of my PC:
Intel i5 760 Quad Core 2.8GHz
Inno3d Geforce GTX 460 1GB 256bit HDMI
MSI H55-GD65 mainboard
Kingston 4GB DDR3
Thermaltake V4
hec raptor 500w
