Removed PC From NT Domain & Can’t Log On To PC (Win XP Pro, SP2)

I had two user accounts in the workgroup. I added the pc to a network domain to update virus definition files. After cleaning the viruses, I removed the pc from the domain. I now am prompted to press ctrl/alt/del which I didn’t have to before adding it to a domain. Now the username that appears by default is the NT username used while on the domain. I enter the password for that username and still can’t log in. My options below the password are OK, Shutdown, Options. I click options and nothing happens. How do I log on with one of the workgroup user account I was using before I joined the pc to a domain? Will plugging the NT cable back into the pc put in back on the network to recognize the password?