Whenever I am downloading something (usually its a video game or a patch update for a video game), my pc will stop working. First, my mouse pointer will stop responding and in a couple of seconds my monitor goes to sleep. At this point, I just shut the pc down and restart it. I have no idea why it is happening. It ONLY happens when im downloading something. Whenever I play video games or surf the web, it never happens. What could be wrong with my pc and how do I fix it?