You possibly have to many updates waiting to get installed.
My take would be to go to the microsoft.com site, get the 8.1 update, install it manualy, then, let the auto update take over.
If you still have the same problem, do the following:
Set the Microsoft Update to inform you about available updates, but let you chose when to download and install them.
You'll get a list of availabel updates. Sellect up to 10 of the OLDER critical ones and install them.
Once they are installed, repeat the process untill there are no more critical updates.
Do the same for the important ones.
Finaly, take a look at the optional ones. Install those that interest you.
Electro
August 2015