mmm
 

all linux system require a username and a password, this is setup always at the moment of the installation of the software, so wahtever is the password and the username you put on, should be what you need, however you may try to reinstall linux and/or try something else like:
Ubuntu 5.10, Fedora Core 4, Mandriva. now if you have never user anything else but windows try out first the KDE shell instead of Gnome