In a case you want to restart a windows server at a certain time, you can use shutdown command plus Scheduled Tasks. Here are step by step:
1. Create a batch file called downtime.bat using notepad.
2. Add this line in the batch: shutdown -r -f -t 30 and save the downtime.bat at c: drive.
-r = Shutdown and restart the computer
-f = Forces running applications to close without warning,
-t 30 = Set timeout for shutdown to 30 seconds
3. Open Scheduled Tasks by going to Start>All Programs>Accessories>System Tools.
4. Click Add Scheduled Tasks.
5. Browse the downtime.bat from c: drive.
6. Follow the screen to setup the day and time.
7. Assign a user who has administrator rights and finish the settings.
Note: the shutdown options may differ depending on the version of the shutdown command.