A lot of pixels keep flickering on and off to black on the screen. And it's not in one spot, so they are not specific dead pixels. Rather, this happens anywhere on the screen where there is too much white, or a high contrast between adjacent pixels. If I move windows around, the flicker adapts itself to the new location.

This is a problem that has been getting worse over the months, to the point now that it's bothering my eyes while I work (I'm a graphic designer).

I've searched the forums and found a lot of posts about general flickering of the monitor, but none that refer to a problem like this. Anyone know what is the problem and how to fix it? Is it the monitor or the video card?

The powerbook is about 3 yrs old now, it's the G4 1GHz model from Nov. 2003, but other than that it still runs great.

Any pointers appreciated!