My iMac is stuck in a login bootloop. After entering the password, I see a white screen for a second and then I am thrown back to the login screen again.
I tried the same in safe mode, and it behaves the same.
I also tried resetting the PRAM, and it behaves the same even after that.
Since this is a hand-me-down, I am not sure of the version its running. I am ok with data loss too.