Hi I was installing leopard on a core duo macbook running 10.4.11 and I put in the leopard install disk, I chose upgrade and the install just barely started and then said "install failed". After this I immediately booted intoo 10.4.11 to see if it was alright, it was. When I try to install again I get to the point where it says select a destination, I choose the harddrive and when I select it and hit continue a dialog box pops up that says your chosen instalation type cannot be done. I then hit option and a dialog box pops up again that says the destanation volume must be completly earased and the new Mac OS X will be installed. what's wrong? Is there anything I can do about this? Do I need to back up and erase and if so what is th best way/ back up program? Also I don't have an external hardrive but do have another macbook next to me with enough harddrive space to fit my back up on.