Windows Shutting Down WITHOUT user's commandARE YOUR WINDOWS SHUTTING DOWN WITHOUT YOUR INSTRUCTION?
No need to worry, there are several reasons for this to happen.
Some of the reasons are
1) Yours windows version is out of date and thereby not genuine,to overcome the error you need to reinstall your system with your needy operating system.
2)your RAM may be defective,to ensure its not defective try removing the RAM from the odd slot provided in CPU and replace it in the even slot.
Sometimes the problem may be solved.