Just happened a few minutes ago. I went to sleep after leaving my computer on as I usually do and then I wake up at 4 am hearing this extremely loud rattling/grinding noise. I thought it was in my room but then I notice it's n Thing in here. I walk out into the hallway and find its coming straight from my computer. I go to shut it off and I notice that the sound is coming from the left side where all the componants are except the hard drive. This sound was around 90 decibels loud. Anyone got an idea what it is?