It is extremely hard for me to believe you have 2 computers with a Windows 7 upgrade that are exhibiting the exact same problem. There must be something in common with the two computers.
Since you upgraded both, you probably set the exact same preferences, but there must be something more than just that. If you are using the same software, maybe you could try another version on one of the computers. Wherever you got it from, get it from somewhere else.
Do you have another network you can use for the updates, or can you put one of the computers in the DMZ?
Yes, some folks are having problems with Windows update. I have never had any problems with 3 beta editions or the RTM version.