physical memory dump

ok, i have an asus A7S333 MB, CPU atholon XP2100+ set at 1733speed, WIN XP home edit.., 256mb ddr333 pc 2700, 60gig maxitor (7200) HD (30gig = c:\..15gig=D:\..15 gig= E:\ ), ATI 8500 128mb video card, on board sound.i have the page filing sys set to 4000 for each logical drive and C:……… just about 1 time every hour my pc will crash and an error will pop up saying
**** PHYSICAL MEMORY DUMP*** what in the sam hell is going on!!! i brought this board and processor cause its matched to WINXP.
i dont know what to do!
any help would be very APPR……..