How to start Automatic Windows Update in Windows 7 and 2008 R2
Windows updates keep your computer updated with all latest updates ( defect fixes and features ) available for windows as well as some of the other software. You can enable the automatic windows update so that you don't have to keep track of those.
Follow below steps to enable automatic windows update:
Open Control Panel from Start Menu. On Control Panel window select "System and Security" as shown above. On "System and Security" window click "Turn automatic update on or off" link.
On the Update setting window Select "Install updates automatically" also choose a install update time such that your computer should be up and running with internet connection at that time. So that windows can download and install updates. Click OK and you are done.