I recentlybought a new tower with windows 8.1 everything was fine until yesterday when i went to watch a vidie someone had posted and the sound was there but the screen wasall green, now i got to the point where the video is there but it won't load u

I recently bought a new tower with windows 8.1 everything was fine until yesterday when I went to watch a video that someone had posted, the sound was there but the screen was all green everything I try to watch has a green screen, I have gotten rid of the green screen but now the video won't load to watch. it tells me I have to upgrade flash player but my computer tells me its already embedded or something like that in windows 8.1. can you help.@marks93255255 or cm17883@yahoo.com!