He didn't use the DDU tool. He used system restore then, afterwards, tried to enter safe mode. The system repair issue began when he tried to enter safe mode - something which is seriously unusual.you didnt need to do any of that.
You should have gone into programs and features. Anything that had Nvidia or Geforce at the front uninstall
reboot pc
install new drivers choose custom, tick perform clean install then just tick physx and driver install nothing else.
Bobs your uncle.
you are still going to have the problem IF you just install everything with the nvidia driver after a fresh os install. Only choose physx and driver. I have not seen anywhere you state what you actually do at driver install.