do you have multiple things open, such as dozens of aim windows, 5+ internet explorer windows open, say a search going on? Those will drain window's resources like a hobo suckin on a bottle of booze. Otherwise you may have some specific program that's just taking up everything.
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It takes 43 muscles to frown and 17 to smile, but it doesn't take any to sit there with a dumb look on your face.
I have fun. Usualy at my own expense, but I have fun regardless