I have a used G4 1.5GHz PowerBook. It has gotten a bit of a screen problem. But it is the most confusing, non-straightforward problem I have ever had with a computer. Starting about a week ago, the screen flickers and tears and eventually the desktop disappears, leaving a thin white gradienty light stripe around 15mm from the bottom. Sometimes brief flickers will bring parts of the screen back, but usually I have to turn it off or sleep it and move it around some. It's not a logic board/video card problem, since it works fine on an external monitor. That seems straightforward enough. Apple store guy says it's not a connection issue, since the thing is plugged in, soldered and taped so that it won't come loose. He claims that it's an LCD problem, which I'd be inclined to believe - except that no flickering or tearing or going black happens when it's in FW disk mode or boots off of a CD (leopard install disc). Sometimes it works for hours, often it happens quickly - but eventually it always craps out on me. Now for the real question - what is causing this crazy irregular screen behavior that ONLY occurs when booting from the HD? If I can't solve it, I guess I'm going to have to start saving for a macbook - but I love my PB. I don't want to see it gone (nor do I want to give up the nice big screen :/ ). Any idea what's up?