Hi Ravenousj,
I have gone thorough your problem and there seem to be several reasons for that.
-Your hard disk might be corrupted
-Your video card may not powerful enough to stream HD videos
From the reasons above, The VGA problem can be the main reason. If you are using a VGA card, you can try updating its driver. If it doesn't solve the problem, it has to be a problem with your hard disk or the system partition. Follow this link for a step by step guide on solving your problem.