Doing BackTrack hard drive install is pretty easy, just follow this installation guide.
Note that this guide assumes that:
You have already downloaded BackTrack, and burned it in a CD/DVD, or created a bootable USB out of the ISO file.
You are going to use your whole hardrive for BackTrack (penetration testing Linux distribution).
Boot the BackTrack on your computer or machine where you will be installing BackTrack.
After finishes booting, enter “startx” to go to the graphical KDE interface.
Double click on the “Install BackTrack” shortcut icon on the Desktop, or you could type in the command “ubiquity” in the console.
Select your Language the click Forward.
Select your location and time zone the click Forward.
Do the same for your Keyboard layout.
Prepare disk space. This window allows you to configure your partitions.
Select “Erase and use the entire disk” (assuming that we are deleting the whole drive and install BackTrack on it).
Ready to install. Accept the installation settings summary. Click Install, and wait till the installation is finished and completed. Restart your machine.
Log in to BackTrack using the default username and password.