hi! i have a late 2008 macbook unibody. my trackpad is acting weird, sometimes when i'm reading something then i move my cursor(using one finger) it scrolls down or up. also i can't use expose. and when i move my cursor it moves slowly and the cursor is shaking. when i fold my macbook then open it again the everything works perfectly then after some time watthe trackpad acts up again. i think my trackpad's getting confused how many fingers I use. should i bring it to a repair center?