NT4.0 PDC computer name change

A Developement server running NT4.0 (PDC)
with the computer name medcelldev and the domain name is medcell, I need to change the computer name as same as the domain name, The error i am getting is that their is a computer name medcell and it will not let me to change the name even this PDC is not physicaly connect to any computer, Thanks in advance.