windows nt 4.0 trust relationship

I have a windows nt 4.0 network. I configured a windows nt 4.0 workstation. the name of the workstation is Transportation. When I log in as administrator, or as a user, There are two options for domains. 1 is the correct domain name, the otehr isTransportation. When I select the correct domain, it does not allow me to log on. When I select Transportation as the domain, it allows me to log on and to access my domain. What do I have to do to get rid of the domain name called Transportation, and to be able to log on with my correct domain name? If i delete the transportation domain name will i lock myself out of my workstation completely?

Help