Basically, it starts buzzing when the computer is not being used and starts buzzing after an hour, possible coil whine?
Coil whine? You shouldn't have too many inductors in your laptop. Though its possible some of the glue that was holding one down broke free
The fan was going crazy, but why would it sound like buzzing?
A fan making a buzzing sound is either:
- Something is loose in the computer and rubbing against the fan (generally a wire)
- The bearing in the fan is going out, and either the bearing is making the sound, or its causing the fan to rub against the fanshroud
- The fan plotting to overthrow mankind, and buzzing sound is coming from the discussions with the other hardware components
- The computer is full of dust/dirt, and is interfering with the fan.
Last possibility
YOUR COMPUTER IS FULL OF DUST/DIRT CLEAN IT OUT.