any special console login?

Hi everyone!
I need to install a nvidia driver, when I swap to console "sudo service gdm stop", I get a puredyne prompt for login:
1- I don't remember having entered any password at all when installing puredyne...
2- I tried my usual one with case and qwerty keyboard change, but doesn't work...

Is there any special trick or am I getting too old to remember me password?
Thanks for help!
Stéphane