what do you have it set up under?
get a console open, boot into the gui, hit your little window key, the one between the left ctrl and the alt. you should have the kicker panel show up. use your arrows key till you get to terminals, the right key will be for ahead, the left for back; always, it doesn't matter which side it opens to. then su, passwd, mousedrake. use the arrows to choose which one, i use the generic ps/2 wheel mouse, then the tab key to say ok. then make sure that you use the wheel to get it going. click on the buttons a couple of times. you should be set after that. you might want to log out and then back in just to make sure that it's working again.