Got a Dell Latitude D820, WXP, all service packs and drivers up to date. Lately, no matter what I might be doing (even walking away and doing nothing at all), the laptop will spontaneously freeze and there is a non-stop LOUD, continuous beep. You can't even push the power button and shut down. Must remove battery and/or unplug the stop the horrible noise. Sometimes it happens after being on the laptop 5 minutes, other times it won't happen until several hours have gone by. I have done some Google searches and even basic hardware diagnostics to no avail. Anybody ever hear of this? Any ideas?