All of a sudden, my 17" PowerBook G4 developed a problem with its display. The screen is divided in two, horizontally, with part of the desktop showing in the top half, and then the same section repeated in the lower half. Two cursers, too. Any application I open does the same thing. The resolution is stretched horizontally and seems to have defaulted to 800x600. Specifics: 1.33 GHz; PowerPC G4; 1GB DDR SDRAM; OS X 10.4.8. Any insight would be greatly appreciated. Thanks.