Can you put a new IP number on a computer to get into it again

I don't know the answer to that one.............. L.A.

Kind of but no

An IP address is internet generated as a unique identifier for logging onto the internet by a computer, and not USUALLY used as a "way to get onto a computer". That scenario sounds more like a server administrator login from the internet than a "computer" login.

Are you trying to get back on the internet, or did you you lose the password to the computer?