Can't Use Updates: [Error Number: 0x8DDD0002] ?

When I try to use Widows Update, I get the following error message: [Error number: 0x8DDD0002] To install updates from this website, you must be logged on as an administrator or a member of the Administrators group on your computer. If you use Windows XP, you can see if you are an administrator by going to User Accounts in Control Panel. Note: If your computer is connected to a network, network policy settings might also prevent you using this website. Contact your system administrator for help with updates. I am using a Dell Dimension 2400 Computer with Windows XP SP2. I have two accounts: Computer Administrator and Guest (account is off).