This morning when I turned on my PC, I noticed a weird sound, as if the fan was wobbly. The odd thing was, if I placed my hand on top of my PC tower, the wobbling noise stopped. I left a heavy book on top of my tower for 5 minutes, and when I take it off, the sound is no longer there. I've been leaving this book on there just so I don't hear the noise anymore. I just want to make sure, could this have been a temporary thing? Or is something inside there just about to break?