Last week, My system got some virus and i overcame that by following some youtube videos. And it involves some registry editing. Now when I shut down the computer using "shutdown" option or "logout" option, screen interrupts suddenly(not showing Windows shutting down). And when I restart, it is showing the message "Windows did not shut down properly". But if I use, "restart" option, it is properly shutting down and restarting, which has no problem. What can I do?