https://support.microsoft.com/en-us/...pdate-manually
This is how you can manually install updates for windows 7 if it gets stuck on a specific update.
I am suddenly wondering whether popping in a windows 7 disc and selecting "repair" may help as well. The other comments about a linux live disc are worth exploring as well.
Also...
You may want to make sure to use avast! and do a smart system scan for basic viruses/malware and programs that require updating. Sometimes if everything wants to update, but doesn't get updated, it's like a ton of things getting stuck in a door way.
Also, if you use msconfig and look at the start up programs, is everything loading up all the time? Or are only the necessities set to start up when you start up your computer?