Originally posted by CrazeD
Probably just dirt in one of the fan bearings. What probably happens, I'm guessing, is that after sitting all night it kind of gets a little stuck, and then when you turn it on it is stiff for a while, then probably loosens up after it's been running.
I'd say you're probably right.
but as for just blowing into it, I dont recommend it. The idea is to get the dust out of the case, not blow it back in.
If your going to blow it out, open the case and use a can of air, with the focus on blowing the dust out.