Windows 7 automatic update caused start-up problem

Windows 7 OS was automatically updated on 9 July 2014. (16 updates)
At the next reboot I powered up the PC, windows loaded normally and the updates installed.
On the next restart, I found that the system halted at the blue welcome screen.
Then after about 2 mins windows loaded normally.
This happened each time I rebooted.
I then restored the PC back to before the update.
When I powered down the updates were again automatically loaded.
When I rebooted, the PC halted at the blue screen but then windows loaded after 2 mins.
The updates were then installed.
I then rebooted and the start-up sequence was back to normal.
My question is how can a windows update have caused this start-up problem.

Further investigation has revealed that the problem had nothing to do with windows updates.
The problem seems to be a Belkin Powered USB Hub.
Removing all the devices connected via the hub but leaving the hub connected results in the start-up problem.
Removing the hub completely resulted in a normal start-up.
When the hub was replaced with a similar Belkin Powered USB Hub, started-up remains normal.
So, it appears the original hub was faulty and impacting on the start-up sequence.

I've never had a hub that didn't cause problems. I never use them except temporarily when I need the extra port.