Recently I found out the hard way that you need to regularly install the patches downloaded by Automatic Updates. Strangely when I decided to click on the yellow shield to install, it kept stuck at “Initializing installation”. I have seen this before.
Stopped the “Automatic Updates” service in your Services panel. In your Windows directory, rename the folder “Software Distribution” to another name.
Start the “Automatic Updates” service will re-create the “Software Distribution” folder. Force an update by running “wuauclt /detectnow” or just go to Windows Update web page.
The patch history for your computer is kept in the “Software Distribution” folder. For audit purposes, you want to print out the patches installed before deleting the folder. Microsoft should really have a printer friendly page for this.