comp turned off while playing payday 2

Sorry I don't know where to post this so I'll post it here. An hour ago, I was playing Payday 2 and my comp just decided to turn off. After I turned it on, I can hear the comp turn on but there's only black screen. This sometimes happen to me only on start up and I'll just turn it off and then turn it back on and everything would be normal. Well after I dusted off my comp, it started again for a few minutes and then it decided to restart and there's just black screen. Restarted it a few times to see if it goes back to normal but no luck, just black screen. Does anyone know what's wrong with my comp? I don't know much about computers, just bought parts and had someone assemble it for me. Comp is about 2 years old. I'm guessing it's my graphics card. Ty