Download this very useful program for you !
a portable firefox that you can store it on a USB key.
Portable Firefox has some specially-selected optimizations to make it perform faster and extend the life of your USB key as well as a specialized launcher that will allow most of your favorite extensions to work as you switch computers.

Portable Firefox will also work from a CDRW drive (in packet mode), ZIP drives, external hard drives, some MP3 players, flash RAM cards and more