Problem with the user name and the password
 

Well, I have downloaded the backtrack 4 r2 but when I started it, it didn't show me the line to enter the user name and the password.What' s wrong?
:scratch:

it's the first time I use it!

BT4 is now stable AFAIK. Yes, the distro will boot into root, I guess because many applocations (like nmap and so on) require you to be the root.
Do you want to install BT4 on the hard drive?
In any case you can change the root password by using the 'passwd' command and if you want to add a new user I guess they have the 'useradd' command.
Hope this helps. I do not have BT4 on my pc right now.

Well, If you are using Back Track as a Live-CD it doesn't prompts you for password, it simply drops you to a root shell (root@bt# )then you have to "startx" to start the GUI.

And if you have installed it then default user: password combination is root: toor


Hope it helps

I have already done that and it didn't start!

What happens when you run 'startx'?
Anyway, it looks like the monitor is not being detected properly. In this case the easiest option would be to select 'safe mode' or a 'safe graphics' option. You would get these options on the very first screen you see.
Hope this helps.