When i am playing, there are some certain parts of the games or even random parts of the game. And the screen flickers green, some parts are green while others are ok. When it happens again i am going to post a picture. Like i said it is random, if i leave and come back it is back to normal. Anyone have any idea of what is going on? Also i am playing on PC.

Only time I had green or red show up on a monitor (old style, not new LCD screens) the monitor was going bad.  But that was the whole screen while yours sounds like its only part.

 

Since you're on PC - are your drivers up to date?  Have you verified the game files through STEAM to make sure there's nothing wrong with them?  Have you downloaded the latest patch?