Unalbe to get system to work

[Walker]

I have a Compaq Presario 1247 Laptop on which I tried to install Debian.  I get to the GNOME Desktop Manager screen but can't get past it.  I type in the user name and password I setup during installation, but all it does is flip through a couple of quick screens and default back to the login.  I don't get an error or anything about a wrong user name or password either.  Is my display set wrong or something?  The GDM screen looks fine.  So what could it be?   Also how do I get out of this screen, the GDM, to the line based version again or even just shutdown the system?   Thanks   ADAM