Hi. I have tried to follow directions to wipe my Macbook clean, but the "erase" options in disc utility are greyed out. I want to sell my macbook but obviously not with my stuff still on it. How can I get rid of everything and start over? I tried putting my OSX disc in but I get a message saying it can't install on this mac. I guess maybe the machine is outdated?? Right now I'm running version 10.4.11 but the one I have on my newer mac is 10.5.4... I don't have any other macosx discs. Why won't 10.5.4 install on this one? thanks for any and all help.