Black Start Up Screen


I recently loaded Tiger on my G4, previously used OS9. When attempting to load software I was asked for an administrative password, I could not remember. I followed the help menu to change password after restarting I now have a black screen with a white message in the upper left corner stating Local host:root#/ and a rectangle.
Restarting again does not help. Can you help, please.
Thank you,
Marlene Parness