See if you can boot from your Windows install medium (disc or stick, free to download) or the recovery drive you made to do a reset or refresh or clean install or maybe even do the old renaming trick from the command prompt (see https://neosmart.net/wiki/fix-registry/ for that).
My original issue was my laptop wouldn't load to the login screen as it was stuck on a windows update saying 64% complete but then it kept restarting and returning to the same screen over and over again.
So i tried to fix this issue with a Youtube video but I've made it worse now as when i logon a screen pops up saying something like my registry files are missing/corrupt or there is an error with them.
Unsure how to fix this issue, any help would be highly appreciated.
If this helps the whole issue started when i was rebooting and clearing my whole laptop - i powered it off as windows was reinstalling late at night so didn't want to leave it on over night. The next day when i powered it on - the 64% update screen kept popping up.