I have been using Backtrack 4 for about 3 months, with very little linux knowledge. I installed backtrack 4 dual boot with Windows 7, couldn't get the atheros 5007 wireless nic that's built in to work. Finally I tried usb live persistent boot, and it works for packet injection and monitor mode just fine. The problem seems to be with windows 7 using the red/blue wireless "button" at the top of the computer. If blue then works well, if red when shutdown and restarted into backtrack it doesn't work. I hope this helps someone. Thanks for your time.