Windows 7: Windows 7 shutting down on its own

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?

In your system event log after the reboot, do you see the events (in this order, although not necessarily consecutive) 6006, 6005, and 6009 (the indication of a successful shutdown/reboot), or do you see any warnings or error 600x events instead?

Yes, in the systems event log I do see the numbers 6005, 6006, 6009. There are no other 600x messages.

OK, so it is indeed a successful reboot as far as Windows is concerned. Does the system do this with the power plan set to "High Performance", or in Safe Mode?

The computer power control is set to balanced. Should I try running it in high performance mode?

Actually, I did change the setting after my last reply and it didn't seem to change anything. Windows still shuts the computer down at random. Any suggestions?

Well, it might be interesting to enable the shutdown event tracker and see if anything gets logged:
Configure Shutdown Event Tracker on the Local Computer

Thanks for the help, interestingly I adjusted a few settings and so far windows has not shut down on it's own yet. I adjusted the computer sleep and hibernate mode to "never" and this interestingly enough seems to have corrected the problem, not sure why this would work though as adjusting these had no impact previously. I will continue computing and see what happens. If the problem reoccurs I will try the fix you reccommended. Thank you and i will keep you updated in the next few days!