domain login help

this is what i messed up if its very clear.
the user was logged in under his domain login, but he is no longer using it on the domain. when i rebooted after taking off the domain and setting it to a workgroup i wasnt able to log on with his username and profile he said he was never setup with a local username and password. i forgot to add a new user before taking off the domain and restarting. i was able to log in using admin. i created a new user profile and added it to all the correct groups. the part i dont know is how to get him back to his original settings but without the domain. or how to get it set back to the domain login to create the new profile from there. i hope im making it a little clearer. thanks