FYI I was getting this problem as well until I stumbled on
a fix.
I recently upgraded from dialup internet access to cable
modem. Once I was up and running on the cable, Windows
Update scan would never go beyond zero percent.
The strange part was when I connected using the dialup
modem, it worked fine.
Then, in an attempt to resolve an unrelated problem, I
physically removed the dial-up modem card from the
machine, and now the update works fine.
Hope this helps.
Sal.