I have a iMAC PowerPC running Mac OS 10.4, that has recently began giv ing problems starting up. Many times, the video on startup is noisy or static filled. Upon several restarts, I can get a good video, but then it stalls on the blue screen with the mouse cursor, but before the dialogue box "Starting MAC OS". No such problems if started in "safe boot". I also noticed that the airport card is now missing in the network section of system preference. I am now using the ethernet connection and it works fine. I have tried starting services from utilites folder, but nothing happens. I tried re-installing the OS, but that didn't help. I even tried reset the PRAM. So what's left and what is the problem, a bad logic board?? If so, is this worth fixing?