Close all windows, then click on start button, type in command prompt, when it comes up right click on it and click run as administrator. If it ask you for a password ***** it in. While you are in that window type in these commands one at a time but make sure you press enter after each command:
net stop wuauserv
net start wuauserv
Close out the command prompt window, type in exit, then press enter to close it. Then go ahead and run your windows update again.