My MBP (Early 2008) model is having a strange graphics issue (see attached pic). Portions of the screen will jump around... for example, half of my dock icons are at the top of the screen, and I have two menu bars on the right hand side. It does this when I'm moving a window or scrolling, and then it jumps back to being OK. The other weird thing is that it ONLY does this on the internal screen... external monitors are fine. I'm pretty sure its not hardware because: 1) If I boot from this HD in another MBP, it shows the same symptoms 2) My MBP has been tested for (and passed) the NVIDIA graphics test, so it's not a defective gfx chip. So I think it's software... but what?