This tweak will speed up the reboot time.

To do this, follow the next steps:

1. Open the Registry Editor click on the Start button on your taskbar, then click on Run and type "regedit" and click on OK to start the regedit utility.
    
2. Expand HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon (see picture 1).
   
   

   Picture 1

3. Create a new STRING value, or modify the existing value, named "EnableQuickReboot" and set the value to  "1".
    
4. The modifications you made will be in effect after you reboot your PC.