you need the portable version which is installed and setup diffrently
At my Dad's house I run Firefox from my USB drive because I don't want to mess with any of his setting and I want my own. Whenever I change something in mine (on the usb drive) it does the same to his on the hard drive itself even though they're in different locations.
What the heck is up with that and how can I stop Firefox on a USB drive from effect another one on his hard drive? Can anyone tell me how to stop it?