not sure if this is software or hardware. My dell inspiron 1525 just shuts down. I have to push restart and maybe it will come back up after several tries. Vista is on this machine. I have run all the diagnostics and can find no drivers or updates or problems I even ran the diagnostic in the bios hoping to find some way of stopping the shut down. I have tried to figure out if it is a problem with the key board or something I am running out of ideas.