My Flatscreen Monitor..?

I have a Flat screen Acer model AL2216W 19 inch and whenever I play a game or watch a movie my screen blinks to black for a few seconds..now lately it does it alot! is there an application I might need to add? also when I restart my Cpu with the Monitor on, there's a black screen with white rain lines then I have to restart it all back up again then it works but only when I play games or videos it blicks alot.