now when I try to use Moviefactory 2, it resets during the audio/video multiplexing. It sometimes will shut off completely, and say NTLDR is missing" ..in the past when it has done that, it would act like the 40 gb hard drive with windows on it is not there...Other times, I just hit the power button, and it comes back on...It then tells me the error was a "kernal_stack_inpage_error"..what might cause this?