Update fails repeatedly

I have Windows 7 ultimate on my old computer but the following update keeps failing and this is the message I get. Any help would be appreciated.

Update for Microsoft XML Core Services 4.0 Service Pack 2 (KB973688)

Installation date: ?12/?01/?2010 9:31 AM

Installation status: Failed

Error details: Code 64C

Update type: Important

Install this update to prevent applications from sending too many HTTP requests while a well-known Document Type Definition (DTD) is included. After you install this item, you may have to restart your computer. Once you have installed this item, it cannot be removed.

More information:
Description of an update for Microsoft XML Core Services 4.0 Service Pack 2

Help and Support:
Microsoft Support

You may try various methods to fix it.

METHOD I

1.Run cmd.exe with administrative previlliges (right click on cmd.exe as administrator)
see here Elevated Command Prompt

2.At the command prompt, type ren %windir%\System32\msxml4.dll msxml4.old, and then press ENTER.

Note After you press ENTER, you may receive the following error message.
Cannot find the file specified.
Ignore this message, and go to step 3.

3. At the command prompt, type exit, and then press ENTER.
4.Download & install manually this hotfix from Microsoft Download Center (not from Windows Update)

METHOD II

1.Control Panel>>Troubleshooting>>System and Security>>Fix problem with WU
2.Reset WU components in aggressive mode http://support.microsoft.com/kb/971058
3.Reset WU libraries Repair & Fix Windows Updates with Fix WU Utility | The Windows Club

Thanks, it has fortunately resolved itself. I tried the methods in the second reply earlier to no avail.