Problem with 12.10 install from USB stick

Question

On a Dell Inspiron E1505, I ran 12.10 from a USB stick, and everything worked well. Then installed it to the HDD (Empty space above Win XP) from within the running instance on the USB stick. Everything seemed to work. 12.10 now boots fine, but it doesn't use the whole screen, and the mouse does not work at all, either from a wireless mouse or from the built-in mousepad. All these things worked when I booted from the USB stick. How do I fix this? Thanks Chris.