The following was lifted from the mozilla site if memory serves me.
In order to create a new profile, you use the Profile Manager.
To start the Profile Manager in Windows, follow these steps:
- Close Firefox completely (select File > Exit from the main menu of Firefox).
- Select Start > Run... from the Windows Start menu.
- Enter firefox.exe -ProfileManager and press OK.
On Linux or Mac, start Firefox with the -ProfileManager switch, e.g. ./firefox -ProfileManager (this assumes that you're in the firefox directory)
// end lift