Cant install BT 5 R2 on portable hard disk

Same problem: I'll state the problem for me. Sounds like a recurring problem:

Computer Architecture: 64 bit
ISO File Installed: Back Track 5 R2 64 bit
Method of installation: Thumb Drive 16 gigabyte


Followed this install using Unetbootin:

http://www.backtrack-linux.org/wiki/..._USB_Installer


Problem:

Boot from USB after hitting f12 to grub.

Boots to root@BT

Typed StartX>Goes to black screen> Have to reboot.