You can create bootable usb stick and install/live use BT4 from that, check tutorials. You can also install BT4 to external hdd. just remember to install grub to usb hdd. Or use virtualbox to install bt4 to external usb hdd.
i want to dual boot my computer with backtrack the problem is my dvd drive is intermittent and the computer wont boot from a usb dvd drive but it will boot from a usb hard drive. can i use a usb drive to dual boot the computer? or will i have to boot off the usb drive always?
You can create bootable usb stick and install/live use BT4 from that, check tutorials. You can also install BT4 to external hdd. just remember to install grub to usb hdd. Or use virtualbox to install bt4 to external usb hdd.
if your using widows/linux you can download a program called unetbootin
here is the link
UNetbootin - Homepage and Downloads
enjoy