I have built 4 identical new systems for friends using Asus N266-VM Mobo and 1800 XP AMD processor. All with 256 DDR mem and Windows XP pro, all work perfectly but the one I built for myself freezes up if left running for 20 minutes. I have no programmes on yet and no screen saver or power management running. (i intend this machine for video editing) if I ever get it running. Have re-installed windows to no avail, anyone any ideas please?