We need to check to see if any errors are being reported.
Let's view the Windows Update log file
Copy and paste "c:\winnt\windows update.log" (w/o the quotes)
into the Internet Explorer address bar and hit Enter.
Scroll down to the current date and look for the error being reported.
Next, Look for the error message in the Windows Update Troubleshooter: http://v4.windowsupdate.microsoft.com/troubleshoot/
Please try the suggestions listed. If error persists please post the error
message from the log file.