I can watch videos on the Internet but when I try to watch them on the computer my screen starts blinking?

I can watch every video on the Internet, etc. Youtube, Facebook... Everything goes fine. But when I try to watch them on my computer, my computer screen starts blinking making it impossible to watch a video, and it won't stop until I stop the video. I also can't turn on my webcam, when I try to do it, my computer screen starts blinking again and totally blocks so I have to restart my computer, and when I open any video editor on my computer or anything in common with videos it starts blinking.