Windows Pro 7 update error

Hello,
Last time I've tried to update Windows I've encountered a problem.
This error message keeps appearing every time:
Windows Update, Windows could not search for new updates, An error occurred while checking for new updates for your computer. Error(s) found: Code 8000FFFF, Windows Update encountered an unknown error. Get help with this error, Most recent check for updates: 22/02/2009 at 22:02, Updates were installed: 22/02/2009 at 22:03.
View update history, You receive updates:

For Windows only."
This is the first time a problem like this occurred, and I've been using Windows 7 Pro for about a year.
Anyone with an idea what it could be about?
Thanks a lot.
