iMac - iMac hangs on the apple logo on startup

OK, so it all started yesterday when my brother wanted me to install Jaguar on his iMac g3 500 because Tiger was really very slow on his and everything was crashing for some reason. I tried to convince him to keep Tiger, but he insisted.

But anyway, we had no problem installing Jaguar, until we turned the computer off and back on.

The first time it loaded up and everything, but then at the part where it says "Waiting for Local Discs" it stopped. After a couple more tries with the same result, i stuck the Jaguar CD back into the drive, but exited the installation, then restarted again and it booted this time. Now, after updating to 10.2.8 it asked us to restart, and now it just hangs there on the apple logo and nothing happens! The little spinning thing doesnt show or anything.

What do i do?


Thanks,

Tanner.