When you are logged in try
That will start the graphical system and you will see, whether your monitor shows something readable.
Generally I doubt, that your monitor is too old, linux is famous for running on old hardware.
Suggestion: Go to the redhat site and search for Xfree86 and configure. They have extra tools to configure the graphical system -- but I'm no redhat user, I don't remember the exact name (Xfree86config ?). Try searching this site too, there is a redhat forum, I believe.