good day sir/madam,

im new to backtrack 5 and i want to try this.
laptop specs:
Acer 4755G i5 VIDIAŽ GeForceŽ GT 540M
NVIDI with Optimus Technology
4GB DDRIII
OS window 7 home premium
first i watch the tutorial on the youtube and follow it.
i download the (BT5-KDE-64) at the http://backtrack-linux.org/ and i check the hascals of the iso. then i download the unetbootin, i format 4g usb stick and use 32fat. then if boot the bt5 live at my usb and when i reboot my pc and 1st with the usb and i set it up to default after a couple of seconds my screen turn to black. i try it again for the second time still im stock before i can reach to type startx. i reformat the usb stick again at repeat it again and still nothings happen. can any one help how to resolve this problems.

thanks in advance.