4 points before you follow these steps -
(1) ensure you backup or image your system so if the steps below fail, you can restore your system (you should do this before any major updates are made to your system).
(2) do not attempt these steps if windows update log shows any updates as pending. Eventually they will install or fail.
(3) in general, when widows update fails it leaves garbage lying about. Windows Update log will tell you which update(s) have failed. Take them one by one from the oldest failure to the most recent. I suggest you boot in between each set of searches and deletions.
(4) turn off install of windows updates automatically.
Use Search (Files and folders), choose advanced options, your primary drive and ensure include non-indexed files etc box is checked. Use the name of the update which failed as the search argument (KBnnnnnn). Once search has completed, select all files and delete them (some files won't delete, but dont worry).
Exit search, go to recycle bin and empty it. If another search finds any files for the same search, you have major problems and this solution will not work.
Reboot.
Repeat for each failed update.
Start Windows update from control panel and attempt each update in turn.
Hope this helps. Further notes may help -
(1) I use an external drive to image my system before any major change
(2) I let Windows Update notify me of updates, but choose to install them myself
(3) I install each update individually. Pain in the ass, but it works.
Cheers,
Les