Step 2 : Downloaded file in .tar.bz2 extension.
Step 3 : Extract .tat.bz2 file in desktop
Step 4 : Copy all files from extracted folder
Step 5 : Paste into
Step 6 : Rename this folder with new version ( Not important )
Step 7 : Run Firefox (Your desktop shortcut is enough to do it )
Step 8 : Now Firefox will upgrade
Enjoy new updated version.
It's not proper way to install Firefox in Linux.
It works very well in RHEL5