oops sorry, didn't see the part about not being able to stop gnome from loading
press ctrl+alt+backspace to kill X/gnome.
then type '#cd /etc/X11'
then '#ls' or '#dir'
you need to find what version of X you're using(hopefully xorg)
you should either see xorg.conf or something like XF86Config-4.
once you've done that you need to get back online the same way you did when you posted this thread and search google for the right mouse settings for your mouse. And also how to use 'vi' 'cos that's what you're going to use to edit the config file. unfortunately my distro comes with nano which made me too lazy to learn how to use vi