Critical Update "Windows Update Agent"

Yesterday (on desktop and 17") I checked for Critical Updates and before it
would do the check, it stated that it had to update the Windows Critical
Update, which it did and then I could see if there were any critical updates.
No critical updates for either PC (which have WinXPsp3).
However, tonight I did the same on the Vista and also got a message about
the Critical Update site needing to be updated. I clicked on OK and then the
computer had that 'green' bar going from left to right for a fairly long time
(a few minutes), and then it just stopped and switched back to the Scandoo
page. I went back to the Critical Update and did a search for Critical
updates, and got a pop-up about some sort of error and to "click here for
explanation." When I did that it had another pop-up screen explaining what to
do if you received any pop-ups about not being able to get/complete update
procedure.
I decided to re-boot. After that I went to the Critical Update page again
and it went right through to check for Critical Updates and found one, which
was usual Defender update.
I looked in Update History and saw two items downloaded were downloaded
successfully. I think the Windows Update Agent 7.2.6001.788 was the one that
was supposed to update the Critical Update page. Since it says "Successful"
and I was able to download the "Defender," I am going to presume that I
shouldn't worry about that original close-down of the Critical Update Page
and the switch back to the Scandoo screen.
#1- Would you presume the same?
#2- Also, did anyone else have similar experience?
Thanks,
Alice
P.S. I checked the desktop and 17" Update History, but neither one of them
said anything about "Windows Update Agent..etc.)

Critical Update "Windows Update Agent"