Win XP media center bsod, neep help

[nine1]

my computer started randomly restarting and i cant figure out why. i thought it was a new pci card that caused the problem but i removed it and the problem is still there. i thought it might be some sort of corrupted system files, so i restored it to factory settings. still the problem is there. please help. i have an external sony dual layer burner and a printer hooked up to the usb ports. i have an external hdd i also hook up from time to time. i got an HP m7730n with winxp media center sp3. any help would be much appreciated. thanks