Factory Reset Gone Wrong

Hello!

I'm trying to factory reset my partner's computer. I've done this before and never had problems. I got all the way through to choosing to reinstall the OS. It was downloading for several hours when it acted as if it was restarting and then a screen popped up that said something like "could not download OS". Anyone else run into this? I should have taken a picture of the screen, but forgot. I was able to get back and restart the install, but I have doubts that it'll work this time. Any suggestions?