Windows 7 Update error 0x800B0100

I've got a user that has been having the Windows 7 SP1 update fail after multiple install attempts. You can probably guess that I've browsed the web several times over and can find no resolution to the issue. The error code is the rather bland 0x800B0100 - the least helpful error code since the days of "there is no article for this error code." I have done the SURT. All it does is install a...