You could just reformat, and it's all your computer after that.
Remember though without updates, and support you would need a good virus, and security suit.

I did a friends computer she got from a pawn shop, it had I think 37 viruses, two porn accounts that could sign into the computer, and a lot of spyware.
After I got rid of them, and installed some security the computer was fast, and safe.

After 6 months of using guest mode and not being able to access the previous owner's account, it finally let me make an account of my own...
I was able to install a simple text program so I can type up my journal and not have to use pen and paper...
Also, I can now save journal entries, photos I took, and videos I took onto my laptop, and they don't get deleted when I shut it down...
Only problem is, it's a Google Chromebook from 2019, it stopped receiving software and security updates a few days ago...
None of my games are working, solitaire, minesweeper, etc, I'm supposed to be able to access them offline, but I can only access them online, every time I try to access them online, Google Play keeps shutting down...
Oh well... at least I was able to install zoom... maybe I can check out a meeting on zoom from my laptop at the food court...