I have a major display problem with the graphics card or something that has grown also into a boot problem. I have run 2 types of virus scans, Norton and Sophos and they didn’t find any problems. So I don’t know how else to diagnose it really or what it is? The computer shut down on its own one day and since then I am seeing my screen lock with my desktop image not centered and pushed off the screen’s boundaries, sometimes a graining or fuzzy layer will cover my whole screen, during boot up I’m getting purple and blue thick vertical “lanes” on the grey boot up screen where there’s the Apple logo, (same when I try Safe Boot) then the full grey screen thereafter but then nothing, I can’t start it up after that. It also doesn’t like to shutdown normally. I’ve been reading it could be a DRAM problem but I don’t think so it seems to be working properly. I have installed gfx card status app and that seems to have helped albeit very little. It doesn’t help during boot or shutdowns at all. I’m running a 2012 MBP 17” with Snow Leopard. Any help or suggestions would be greatly appreciated, thank you.