i've read where deleting the entire contents of the Downloads sub-folder of the Sofware Distribution folder (C:\Windows\Software Distribution) and restarting machine restored the Updates for some people.
Worth a try, maybe. Or, via searching, I found this short tutorial on Major Geeks which adds a few steps. Doesn't seem too complicated.
On your PC there's a folder called Software Distribution that stores temporary files during Windows Updates. Under typical situations, you should leave this folder alone. However, if you have an issue with a stuck Windows Updates, then deleting this folder can often resolve those problems...
Edit: added the Downloads portion to the sentence.
Ohhh... about reinstalling/reformatting the Drive OS after a infection is one of the safest ways to go and totally support @SecurityNightmares claim.
The reason is simple and depends on AV in use. You can have Enterprise grade Security after a infection. Since the IT-Guyz are responsible for the systems. They reimage (Reinstall / Reformat) the Systems after initial investigation.
Fixing a system is time-consuming and if a backup is in place this can save time and hassle - That is why also here ppl recommend to backup the system. To be up and running ASAP.
When you have a System you love and all the settings are just right a Backup is just a super safe approach. You can be up and running in MInutes depending on HDD/SDD and Backup Source/Software.
There are nice and easy Professional Solutions like VEEAM Agent for Windows (FREE).
You can never know if some kind of stuff still is in your system. You can scan with all the tools there is always that one case of something exotic. It is not that ppl have network monitors, know every DLL/EXE and so on... with Hash Values and analyze traffic 24/7.
So to come to a point:
Time spent on Fixing the issue and not know if the system is truly safe - Compared to just Restore from Backup ^^