Many a times people like to sleep on music, but the problem is that the comp will continue running the whole night. Here is how you can create a countdown timer to shutdown your comp in your specified time. Go to run in start menu and input this command
shutdown -s -t 3600
this will create a countdown timer which will go off in 3600 seconds (1 Hour). you can replace the 3600 to any time limit you want the comp to shutdown ,but remember the time should always be expressed in seconds i.e if u want the comp to shutdown in Half an hour you have to write 1800 and so on...
If you are as lazy as me and don't want to input the command each time, then create a batch file or shortcut Batch:
open a notepad and type shutdown -s -t 3600
now in the files menu select "save as" and save this file as Activate.bat Just double clicking this file will activate your timer