I was surprised the other day when i installed a backtrack linux distribution and couldn’t login. What you should know about backtrack 5 is that it comes with an already pre-configured username and password also the first thing you come across after booting and typing the username and password is the terminal( which is a nightmare to most people). The details below will assist you in getting around some of the difficulties.
The default username is: root
and the default password is: toor
to start the graphic user interface of backtrack 5 you need to type: startx in the terminal
startx command can also be used with other linux distributions
to shut down type: poweroff or shutdown -h now
To restart: type reboot