Hi all, I'm using a Powerbook G4 which is about 6 years old, it's the original one, lovely sturdy with a silver keyboard (girly comment lol). It came with Panther, and i used the system update over time, it's now up to version.10.3.9. I need to upgrade for obvious reasons. Two questions: 1. Would it run better using Tiger 10.4 or Leopard 10.5. If i upgrade to Tiger, does it have to be 10.4 or can it be 10.4.1 etc.. i've read here and there poor reviews about Leopard and some say Tiger is better. 2. Where can i buy either? I can't find the retail version anywhere so frustrating ! though Amazon had Leopard at a whopping $299 !. I'm told Ebay is the place, but how come people sell their CDs when I read somewhere about 'not being able to use a disk that someone else used on their machine? how does that work?. 3. Spec of my G4 is Mac OS X version 10.3.9 Processor 1.67 GHz Power PC G4 Memory 512 MB DDR SDRAM (i've never added memory to a computer, do i need more ?) I need to get this sorted for uni asap, thanks for your help with this .