I think it was this file i downloaded that caused this problem but i can't run any movie file (Window's Media Player and Quicktime). Whenever i try to run it, it slows my computer down severely. My screen turns black and then turns back to normal. I can only watch videos are through streaming sites like Youtube. The only way i can get it working again is to reboot my computer. This problem doesn't affect my internet or anything else, just my video player. What is the problem because i really want to watch videos through the movie player again. Please help!