I have a powerbook 1.67GHz machine and the video card or driver (...or something!) is on the fritz. The "internal" screen frequently gets totally scrambled, but if I am hooked up to an external monitor in mirror *or* extended desktop mode the external screen appears completely normal. The problem is intermittent and usually goes away after ~1-10 minutes, but may reappear after after a few tens of minutes or hours. It seems to happen most when I start using the laptop in the morning, so perhaps it is related to using the video card when it is "cold." Also, a screen capture (command+shift+3) of the internal screen appears totally normal (probably not surprising). I feel like this problem started after I installed flip4mac, but have since uninstalled every remnant (...I think) and updated the OS to 10.4.7, but still the problem persists. I ran Apple's hardware test (boot from the service CD, ran the test overnight), but the test only returned normal results and no problems. Any ideas? I'm still under AppleCare so I can send it back, but because it is intermittent I'm afraid it will just get sent back unrepaired. Or, if it is a software problem they might charge me to fix it. Thoughts. I've attached a digital photo of the scrambled screen. Looks bad, eh?