So I've tried to perform a Windows startup repair by booting up Windows from a USB flash disk. But it was unsuccessful.
So I've tried to manually fix the boot record by using various commands:
Bootrec /fixmbr Bootrec /fixboot Bootrec /rebuildbcd
None of them worked.
This resulted in
Failure when attempting to copy boot files
Finally the one command that fixed the problem for me was the following:
BCDBoot c:\Windows /s c:
Thanks goes out to this post from AIK IT Support!