I picked up a used PowerBook G4 1.5Ghz Al today. I stopped at my local apple retail store and purchased an Extreme Airport card, which I was assured would work. I also bought a copy of Leopard to install. Got home, tried putting the card in, with the version of Tiger it already had installed. The system would pause/hang on the grey screen for forever, or after a hard restart, would load the desktop background and then freeze up. When it would freeze, it also would no longer move the mouse. I figured it was a incompatibility with Tiger. Pulled the card, and installed a fresh copy of Leopard. I then installed the AirPort Extreme drivers from the disk. Inserted the card and.....was right back to the freeze on either the grey screen or before the login-prompt, with the mouse also unable to move. I also want to add that I've tried a PRAM reset as well, no change there. Also, there is no warning message about kernal panic of things of that nature. It just stops. Any ideas? ****Edit***** I take that last part back. After leaving it frozen for several hours, I hard restarted it and got a kernal panic "restart" message and now keep getting them.