Hello Recy Rana
The information that you gave is too brief to diagnose the issue.
Just asking, did you try shutting down or restarting the system from the command line? If not yet, here's how you can do:
Open the CMD window with administrative rights. (You can right-click the CMD icon and can choose Run as administrator from the bottom of the screen (Windows 8).
Once on the command window, you need to type 'shutdown -r -t 00' (without quotes). You can replace -r with -s if you want to shut down the system.
Press Enter key and see if the computer restarts. In most cases this works and if same happens in your case, you can create another user account and try to restart the computer normally.
In most cases the above trick works. But if the problem still persists, you need to provide more details about the issue before we can give you exact and foolproof solution to resolve the issue.
Hope this is helpful.