I have a new computer which was working fine before activating windows 7. Since activation windows shuts down, (safely), on its own for no apparent reason. It doesn't matter if I am surfing the net, gaming or whatever app. I am doing, the screen flips to windows and goes through a safe shut down. There also does not seem to be a specific time period associated with the time to start up to shut down. Sometimes it's 5min, sometimes 45min. Any ideas?