Creating multiple profiles in Mozilla Firefox.

Many folks don't know that they can create different user profiles within a Firefox browser quite similat to creating different users in a OS. Different profile for different persons sharing the same computer is a cool feature respecting the privacy of each users. The process is quite simple:

1.  Close Firefox, make sure Firefox is not running, check in taskbar.
2.  Goto start > run 
3.  type 'firefox -p' 
4.  A new dialog box will open up, asking for creating the profile , then follow the instructions.
5. You can make the firefox to ask you everytime to use a particular profile, by unchecking the checkbox -Don't ask at startup.
6.  Click on 'Create new profile'
7. Click next & follow the instructions. Select user profile name. You can also specify the folder in which your user profile will be saved.
8.  Click finish.

If you will try to open another firefox with different profile, firefox will open another instant of the same profile.
To override it & open multiple instances of firefox with different profile, follow these insttructions.

• open cmd [start>run>type cmd & enter]
• goto firefox folder [cd "c:\Program Files\Mozilla Firefox"] 
• type the command 'set MOZ_NO_REMOTE=1' & press enter (without single quotes).
• type 'firefox -p' 
• Choose user profile dialog box will appear, 
• Select the profile, you want to use & click on start firefox button. 

References:
http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows
https://developer.mozilla.org/en/Command_Line_Options