Leopard won't install on PowerBook G4

I have a PowerBook G4, with OS 10.3.9, a 1.5 GHz Processor, and 1 GB RAM. But when I try to install Leopard, it says that the hardware cannot be installed. Why is this/how can I install Leopard?

G'day and welcome to the forums.

You are trying a clean install and not an upgrade?

Sounds like you are using the disc from another machine. You need the full retail install DVD as the system install discs that comes with new machines will work on that model exclusively.

Is it like one of those grey install dvd's?
If it is, it's a machine specific install dvd, and cannot be used with your PB.

You're gonna need a retail DVD... like Harry said;D