Round and round we go, the Gear has no place to go?

First go-around...

After bringing my G4 out of mothballs and trying to reboot it wouldn't get past the Apple/grey page.

Second go-around...

Then after some doing I was able to get the system install disk to run. I stopped that to put in the Leopard install disk and was advised for the 'destination' page pick the 'upgrade' box, then run through the disk. This way I wouldn't lose anything already stored on the hard drive. After successfully completing the install (computer wording) it did it's restart as per procedure but when the Apple/grey page came up and the gear started turning... the gear seems to be stuck in a perpetual turning... So, how to get past the gear turning procedure to have the screen for entering the password?

Any assistance would be greatly appreciated... thanks