If you selected the option to have shared media available during your setup of Media Center, you will notice that your PC will no longer enter Sleep Mode. Media Center disables the Sleep Mode function to allow the shared media to be accessed. To restore Sleep Mode functionality, do the following:
1. Go to the Control Panel.
2. Select Classic View in the left pane.
3. Double-click Power Options.
4. Go to the current power plan and select Change advanced power settings.
5. Select Change advanced power settings.
6. Scroll down to the bottom of the list.
7. Expand Multimedia settings.
8. Expand When sharing media.
9. Click on the setting so that it changes to a dropdown.
10. Select Allow the computer to sleep.
11. Click OK.
12. Close the Edit Plan Settings window.