Just about 30 seconds ago, i heard some squaking, and i'm wondering if and why a computer would squeak...is it the fan I'm guessing? Because my chair with wheels is oiled, so what is squeaking?
A fan would get my vote, put you finger on the bearing mount and see if it feels hot. If it is you can usually remove the paper/plastic cover over the bearing and place a small drop of 3in1 oil on it, this isn't a fix, if the bearing is going out it will be on borrowed time.