About all I could recommend at this stage... would be to try
creating Win10 install mediaAnd then try using one of the "repair" options when booting... I would just make sure that you backup all your important stuff BEFORE you try doing any repairing/restoring... I ran into an issue a while back and attempted to do a "dirty" reinstall, and apparently Microsoft's idea of "will keep all your data" is a bit different to mine!
I lost a bunch of stuff because it wiped certain directories that I didn't think it would...
It might also be worth considering going as far as backing up, then completely wiping the PC and doing a clean install...