Unfortunately, re-formatting the Backtrack when it appears as a "Removable Drive" on your computer will erase the system firmware that the unit requires to boot-up as a standalone unit independent of being a flash memory drive.

Try performing a "hard reset" (inserting an extended paper clip into the hole on the side of the unit and gently depressing the microswitch for 5-8 seconds). What happens to your unit after doing this?