If anyone is having problems with yesterdays windows updates, I may have a solution for you. After spending a couple hours with Microsoft support, it seems that one of the updates (most likely Defender) may be incompatible with your anti-virus program (in my case AVG).
You can try disabling you anti virus in msconfig to see if it works for you.
Just thought I would pass that on, since I spent the day on the warpath with Microsoft and don't wish that on anyone.