How to fix can't change windows update settings.

For Windows Vista/7

Click Start and type regedit in the Search Programs and Files field. Then right-click on regedit in the programs list and select Run as Administrator.

Within the Registry Editor, navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU.

On the right side of the window, locate AUOptions and NoAutoUpdate. Delete both of these registry keys.

Reboot

You should now be able to edit Windows Update