I have a dual 2.0GHz G5 Powermac that I want to reformat. I had upgraded the machine from Jaguar to Tiger but now I misplaced my Tiger 10.4 DVD. I have a 1.8GHz G5 iMac, would I be able to use the software disc from the iMac to reformat the G5 or am I forced to go out and purchase a new Tiger disc?