boot camp update stuck

I HAD a working Windows partition, but for some reason the Boot Camp icon in the task bar to restart as a Mac was no longer there.

I decided to try & update the Boot Camp drivers to fix this so I downloaded them to a flash drive using the Boot Camp Assistant.

i rebooted into Windows and began the install.

It appeared to be installing the files, then restarted. When it restarts, I get the blue Windows logo for a bit, then the spinning circle of balls appears, and that's where it stays.

I let it sit overnight and in the morning I had the same thing.

I don't know how to fix this. I can't get it to boot into Windows now.

I do have a back up on an external drive that I made just before I tried to update.