I cant connect my Guitar Hero controller to my PS3 HELP!!!?

Ive followed all the instructions in the book. Ive connected the sensor to the USB turned on the Playstation 3 then pressed the PS on on the guitar it just flashes as does the sensor then all the lights go out. It wont ign the controller, if I turn on the normal wireless controller it is igned to "2" so something must be happening. I also bought my bro one for xmas and he is having the same problem. Ive followed all the instructions and its highly unlikely that ive bought two faulty guitars so what am I doing wrong??? I just wanna play my new game boo hoo!!!!