KB979909 and KB979906 Updates Fail

I have tried many times since 6/11 to install the subject updates with no
success, with the yellow shield reappearing again and again. I keep getting
the following 'Automatic Updates' message:

Some updates could not be installed:
Microsoft .NET Framework 3.5 SP1 and .NET Framework 2.0 SP2 Security Update
for Windows 2000, Windows Server 2003, and Windows XP x86 (KB979909)
Microsoft .NET Framework 1.1 SP1 Security Update for Windows 2000 and
Windows XP (KB979906)

(I also found an 'Error Code' 0x643 listed in the 'Installation Failure'
detail screen.)

I have seen various recent messages in this discussion group with the same
or part of the same issues, but listed suggestions (e.g. editing the
registry, finding, uninstalling and reinstalling previous updates, etc.) are
much too technical for someone like myself with limited troubleshooting
ability.

Is there an easy fix?

I am running Windows XP with service pack 3. I have had this computer (Dell
Dimension 8400) for 5 years, have always installed the updates as soon as the
yellow shield appears, and have never had a problem until now. If I cannot
get the updates to install successfully, is there any way to block these
particular updates from causing the yellow shield to appear?

Any help would be greatly appreciated! Thanks!

I am having the same exact problem, on Compaq machine. Any help would be greatly appreciated here too.

I am having the same problem with KB979909. Tried several times to install.

Tried manual download worked fine. But my computer still wants to download the same files when I have automatic download activated!

I am still having this problem. At this point, I'd just like to permanently
cancel/block out the attempted 2 updates. Is there a way to do this?

You put your right foot in,
You put your right foot out;
You put your right foot in,
And you shake it all about...