OK here is the deal. I am beginning to hate yahoo messenger! HELP?

I decided to download messenger. well when i did all was fine and dandy until one of my friends said my name was coming up on it. How do i not get it to say my name? I want it to say my ID. I have tried numerous things. I think it won't let me because to have a yahoo email i had to put in my first and last name. Could that be the reason? Someone please help before i break my computer when i lose my temper!!!!