Windows is set by default to install important updates automatically. These are usually issued once a week on Tuesday unless something critical occurs.
You can turn off the automatic updating of Windows. If you do it will be important for you to go in Windows Updates (via Start menu or Control Panel) every week or two and install Windows updates. These updates fix problems with Windows and Microsoft programs and also fix security problems discovered.
To change Windows Updates go to Windows Updates in the Start menu or Control Panel. Then choose Change Settings. Important updates will be marked wit Install Updates automatically in a drop down box. Click on the drop down box and choose Check for updates but let decide whether to download and install them. You will still get popups on the task bar telling you when they are available but now you will install by your schedule. Click OK and you are at the screen you would install them from. You will click Install button to install any updates.
The next part is only for advanced users and shows how to change the Shut Down button from installing updates at shut down (and causing long delay on shutdown and startup. It involves a registry edit and you should only edit your registry if you know what you are doing. If you make a mistake in the registry you can destroy your Windows so that the only option is a clean install. Be extremely careful. If you want to do and not sure find someone who knows how to assist you. WARNING registry errors can destroy Windows, do only if you know how to edit Windows. If you do this backup your computer and registry first to an external drive.
To make this change run REGEDIT. Then go to HKEY_LOCAL_MACHINE\ Software\ Policies\ Microsoft\ Windows\ WindowsUpdate\AU. Each of those are different levels in the registry. The registry keeps information on how to run Windows and the various applications.
Change the DWord value NoAutoRebootWithLoggedOnUsers to 1 if it is there or create a new Dword and value of those. Exit and reboot.
Now when you choose just Shutdown that is all that happens. However you now have an option on the Shutdown menu to install updates which does that and shutdown as the shutdown option had before.
I hope the first part of the article is helpful to everyone in being able to control updates if you want (just remember you now control when and you must run updates regularly). I hope the second part shows that you can control Windows to more the way you want but it has to be done very carefully or you could lose everything on your computer.
Thanks Todd for the question