Yeah, or maybe it is not recognizing that it is a laptop or something. But vertical scroll worked so... I'm sure there is also a config file that you can edit somewhere; I remember doing that in the old days. Unfortunately I don't remember much about it now.
What happens if you boot from a live cd, do you have that option then? You could also try to make a small partition, and install it there. Then you know whether a complete reinstallation will help.