When I try to watch videos which use flash players (eg youtube, megavideo ect) there is large green solid rectangle shaped pixels on within the flash player not the general computer screen (as shown in the picture). This only popped up in the last week and I just recently bought this laptop. Any idea what's going on?
I suggest you to test updating the video codecs installed in your system, update the video player being used and test if the issue persists when using video files saved in your hard drive.
In addition check with your computer manufacturer to update all the drivers loaded in your computer.