Complete System freeze

Recently, when running windows 7, the entire system will completely lock up after a few hours of use. This has happened the last 3/6 times I have been in windows. Whenever I am in other, non windows systems, this lockup does not occur, from what I can tell. What happens is the entire screen will freeze, it won't respond any type of input, and whatever sound that was playing at the time will start repeating at a rather fast rate. This is a relatively freshly built system, with no other problems from what I can see. I have been monitoring all of the temps each time it has happened, and they all have appeared normal and within regular limits at the time.Does anyone have an idea on what might be causing this? (I have checked the system and application logs, but nothing out of the ordinary has shown up there either)