PC loses signal to monitor

While I play a video game, FPS in game start dropping and the monitor loses signal, but the PC is still working. Today I tried the thingy with Capslock and after I pressed it two times, my PC stopped. After I turned it back on it booted, but a black screen appeared and not the logo and after that it rebooted itself and now it's working. I can't play video games at all anymore.

My CPU is i5-3450 3.10 and graphic card GTX 650.

I had this problem even on previous version of windows.

I can watch movies and videos on chrome fine, but when I play games the hell unleashes.

Please help me .

Try to disable hibernation and check if there is any malware on the system.

Already done all of that, but it seems like changing my resolution to 1600x900 may have fixed it, at least for the moment. Don't mark the post as "Solved" yet, because the problem might re-appear.