Unable to boot backtrack 5 live cd

Hi. Im already having ubuntu and win 7 in my lappy I want to install BT also

so i downloaded Bt 5 gnome 32 and burnt it to a dvd.

when a boot into the cd it shows me a command lie type of screen may be," BOOT:\ "

I simply press enter then isee ascreen which asks me to select the backtrack stuff igo for the first option(command line probably).

Then I see a screen with BT logo and Bt slogan and nothing happens for hours.

Can any one help me?

by the way mie is inspiron 15R,i5.