Just installed an Airport Extreme Card into my Powerbook 15" 1.25Ghz. I installed the software first, then put the Airport card in. It didn't work. I updated the software on OS X and it didn't work. It will only start up if my Airport Extreme Card is not in the computer. If it is installed, it will not start up. I have ensured it is firmly in place. What can I do? There's no startup chime or anything, just black screen. It's the FW800 model by the way.