When ever Windows 7 installs automatic updates through Windows updates, your PC will be forced for a reboot for the updates to take effect. Almost all Windows updates require you to reboot the PC and it can be annoying in case you are working on something important and Windows automatically reboots your PC. But you can disable the automatic rebooting by Windows after installing updates.
To disable automatic rebooting, open Policy Editor. Open run command (Win + R Key) and type gpedit.msc and press enter. In the local policy editor, navigate to Local Computer Policy-> Computer Configuration-> Administrative Templates-> Windows Components-> Windows Update.
Double click on the option “No auto restart with logged on users for scheduled automatic updates installation”. Select the Enable option and click save.
If the status is set to Enabled, Automatic Updates will not restart a computer automatically during a scheduled installation if a user is logged in to the computer. Instead, Automatic Updates will notify the user to restart the computer. Although the automatic rebooting is disabled, Windows will prompt/remind you to reboot the PC.
Make sure that you reboot the PC manually otherwise, Windows update might not be installed on your PC.