I just got an imac g5 that a friend was throwing out. When I start it up it gives me a flashing globe, then a flashing folder with a ? and the apple face. After a few seconds it goes to the light grey screen and instead of the apple logo it shows a circle with a line through it. I have the retail (black front) panther install disk. When I attempt to boot up from the disk by holding "c" it gets to the screen with the apple logo, the logo then shifts slightly to the right and the computer freezes. Any suggestions on how to get through to the install disk and is the reinstall even the right solution?