Stop Windows from Restarting Your Computer After Updates

Click on Start menu or screen and type "regedit" (no quotes). Start the Registry Editor that pops up.

Navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU

If "WindowsUpdate" does not exist, create it. To create it, right-click on the "Windows" key in the sidebar and go to New > Key. Name the key WindowsUpdate, then right-click on that key and create a new one called AU.

Click on the AU key and, in the right pane, right-click on the empty space and choose New > DWORD (32-bit) Value.

Name the new DWORD:

NoAutoRebootWithLoggedOnUsers

Double-click on the new DWORD and give it a value of 1.

Reboot your machine.

Download Reg file

Tip from http://www.howtogeek.com/139993/prevent-windows-8-from-restarting-your-pc-after-windows-updates/