I have a 500 MHz iMac G3 that booted to OS 10.2 when I got it. I put Panther on it, but now it's hard to see any pages at all and it crashes at almost every page. I tried upgrading, thinking that might help, but it spits out the Tiger upgrade disk after a few seconds. I have the original gray disks that go to this computer. Should I see if it'll take those? Any idea why it's behaving this way? It needs a new battery, but should have enough RAM to handle Tiger. It no longer shows as having OS 9 installed either.