In JonDoFox, you may choose File->Load other profile->[Profile name] to switch to another profile, e.g. to the Firefox "default" profile. You may thereby also launch more than one profile at the same time.

Alternative:

First, close all Firefox windows.

Then you may start the Firefox profile mananger by using

Windows

• Start/Windows-Icon->Run or
• Start/Windows-Icon->Start Search
• Start/Windows-Icon->Programs->Accessories->Run
• Start/Windows-Icon->Programs->Accessories->Prompt
• Windows-Key + R

Linux / Mac OS X

• the shell/command line

There, type:

firefox -P           (Please honor spaces and upper/lower case!)

You will find more information about the profile manager here.