Ubuntu studio cant find nvidia module after install of grub repair

I wanted to fix my grub. i couldn't get it to update at all or when it did it didn't seem to do anything. I tried to fix it with grub repair only to reboot with a unfixed grub and the nvidia driver had gone missing.

now i boot up and get "nvidia failed to load the nvidia kernel module"

i have purged and reinstalled the driver multiple times without success.

well poo. I solved the problem but now the question is why it happened. it seems to have fixed it's self. after tuns of install/purge/config/etc. it's working. i want to understand what i did wrong.