CHANGE ACER ASPIRE SCREEN

Hello,

My Acer ASpire One have been locked. When I boot it become the screen log name. I have never put a password on my netbook, but in this machine the Aministrator Name is different. (no ADMINISTRATOR),
saw it once. My problems is I would to change the way the netbook present the log dialog. Now it appear the box in which you type both, the name and the password. I would like to change it to the one that has all the names and you just click to place a password.