At the risk of sounding arrogant, the answers given above are completely wrong. What is happening here, is one of your updates has failed to install properly and keeps trying.
The first thing you need to do is alter your Automatic Updates settings, in order to find out which update is failing. (Alternately, you could visit Windows Update site, and it will also inform you of any updates which have failed to install)
Start
Control Panel
Security Center
At the bottom you will see "Manage Security Settings For;" ; click on Automatic Updates
Change from "Automatic" to "Download Updates for me, but let me choose when to install them"
Now rather than mindlessly attempting to install the same failing update, you will have a little yellow shield down on the task bar, that proudly informs you;
"Updates are ready for your computer. Click here to install these updates..."
When you click on it an Automatic updates window will open with two choices;
Express or Custom
When you click Custom a list of all pending updates will display, take a moment to jot down the pack #'s, aka;
K8928090
KB929969
KB929399
etc. After the window pops up again, informing you you have updates ready to install, look for the # of the pack you just installed a moment ago (it will probably be the only update listed)
Now take this pack # (KB...whatever....), and do a Google search using some crafty search terms like "cant install KB...whatever, the number is..."
Chances are outstanding you are not the only one to have faced this problem. The top two or three results should be sites (preferably Microsoft) containing a "work-around" to solve your issue.
That is the correct way to resolve failed updates, and the end of your problem.
Hope that helps : )