i was just wondering what causes this. often times after my computer has been on all night or for several consecutive hours- downloading a large file, running a bot that does diablo 2 runs for me, or just on and doing nothing, it will be very laggy when i go to use it and i have to restart for it to speed up again. i was wondering what causes this, anybody know? and is it possible that my comp might be being harmed somehow? i'm running a windows xp home and my box is a pentium 2.4 ghz with 512mb ddr ram.