Two of our handlers noticed some weirdness with Microsoft update. See the image.
Update (handler Kyle Haugsness): Several people have responded with proposed fixes. Unfortunately, they are all different. The suggestions are diverse: disable all anti-virus (especially Norton and McAfee), re-install Internet Explorer, delete the Internet Explorer cache, re-install XP service pack 2, flush the DNS cache, and log-in as local administrator.
So the moral of this story is: several people seem to be having the problem occassionally and if this is affecting you, good luck in figuring out the right approach. This one seems to have no consistent cause or solution.