I am using a MacBook Pro running snow leopard. It is a late 2008 model I think. The LAST model that had a physical mouse button. I have successfully installed Ubuntu 8 to a flash drive (I also tried Ubuntu 10) and the computer restarted after install as normal. When I held down the ALT key to boot from a flash drive, it did not show up at all. I only had Macintosh as an option. Help!