I found an answer, in a reply from Robin Walker [MVP] to another question re:
error 0x80070005.
What I used to fix the problem was Dial-a-fix, available at this location:
http://wiki.djlizard.net/Dial-a-fix
I used SFC /PURGECACHE to clear the DLLCACHE prior to running SFC /SCANNOW,
as recommended. Then I went to the Tools section for the Reset Permissions
option.
When it told me (in the Tools section) that I did not have
C:\Windows\System32\secedit.exe, and when it suggested it, I downloaded
Dial-a-fix-medium (
http://djlizard.net/software/Dial-a-fix-medium.exe), and
ran it. If I had XP Professional, I would have used Dial-a-fix-light, which
is stored at snapfiles
http://www.snapfiles.com/php/downloa...g=269312&loc=2
Microsoft Updates are now working. (Thanks, Robin.)