Okay, periodically and randomly my computer will just freeze up for a second or up to 5-10 seconds, then release. My mouse will jump to wherever it would was supposed to go as I spin it around in a frustrated atempt to do something or anything. If I'm playing an MP3 it will repeat at the one note for the time it freezes then continue as if nothing has happened. It's not critical and it hasn't happened while I'm playing a game or anything, but it has eluded me so far and I want to know how to fix it! My specs are as follows:

P4 2.0 GHz
512 RAM
MSI 845GMAX M/B
GeForce 4 Ti 4600
SB Live

I have my system loading as little as humanly possible but I don't know what else to cut out. Any help would be greatly appreciated. Thank you.