I doubt people should take advice from someone who said you cant click a button or two to upgrade or install software on Linux...
Official instructions on how to install Firefox, which is as easy as it gets but apparently still requires typing some long and incredibly stupid command in Linux. Why must you constanly lie?
http://www.mozilla.com/firefox/releases/1.5.html#install
For Windows, Double click the Firefox Setup 1.5.exe installer to start the install.
For Linux, Extract the tarball in the directory where you want to install Firefox:
tar -xzvf firefox-1.5.tar.gz