1. Start the Registry Editor, and find the following key:

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

2. If

On many computers, you won't see the “WindowsUpdate” key. 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 and from now on, Windows will not force you to reboot after installing updates. Of course, when you install updates, you should still reboot your computer—and that responsibility is now on you—but this makes sure Windows doesn't catch you by surprise.

Again, this registry key has been around for a long time, and should work in Windows 7 as well (but we thought it was worth revisiting for Windows 8). You can also perform the same task with the Group Policy Editor if you're on Windows 8 Pro. Hit the link below to see how.

Prevent Windows From Restarting Your PC After Windows Updates | How-To