Critical Installation Error

I am using Windows 2000 Professional and I have been updating the critical
patches from windowsupdate regularly. In the last three occassions, I
encountered same failures in installing the following patches, do you have
any ideas of what I could do? Thank you.

===

Not All Updates Were Installed

The following items failed to install. To try installing them again, click
Review and install updates, and then click Install Now again.

Cumulative Security Update for Internet Explorer 6 Service Pack 1 (KB889293)
Security Update for Windows 2000 (KB873339)
Security Update for Windows 2000 (KB885836)
Security Update for Windows 2000 (KB885835)
Security Update for Windows 2000 (KB840315)
Security Update for Windows 2000 (KB842526)
Security Update for Windows 2000 (KB841873)
Security Update for Windows 2000 (KB841356)
Security Update for Windows 2000 (KB840987)
Security Update for Windows 2000 (KB841872)
Security Update for Windows 2000 (KB841533)
Security Update for DirectX 7.0 (KB839643)
Security Update for Windows 2000 (KB839645)