I don't know the all the details because it is not mine, but my friend has an older Powerbook G4 15" that developed the following symptoms... 1) It would not boot, the flashing ? folder icon appeared 2) It would not power on from the battery, and the battery won't charge 3) Now when you turn it on, the display just makes random colored bars across the screen (somewhat akin to a TV test pattern), and nothing else. Tried resetting the PMU, tried plugging in a second monitor but the monitor gets no signal. Any thoughts? Possible logic board failure? Thanks!