I have been having this problem for a couple of months now. I currently have 25 Important and 5 Optional Windows Updates downloaded onto my computer, but when I restart/shut-down, the updates fail. It usually ends with the message "Windows update failure; reverting (or reconfiguring) changes" or something like that. Then I can log in and use my computer like normal.
I have been ignoring the issue since everything was working until recently. I have started to notice things are slower (Internet Explorer, Chrome) and updates for Avast and other programs seem to get stopped before they can begin. For example, Avast is now telling me I have no internet connection, even though I am watching youtube videos while I try to update Avast.
Please let me know how to get these updates to install properly. I hope that fixing them will also resolve some of my other issues.