I have an handed down Mac G4 from my dad, it was freezing alot (it had OS X 10.4.2). So i decided to reinstall OS X, unfortunately the copy of Tiger has disappeared so i had to reinstall OS X 10.2.8 .... i know i know. So it worked fine after that, til i decided to buy Leopard. When i do the install it, it gets through about 15% of the install and stops saying "could not validate "ESSENTIALS", please contact software manufacturer". Anyone else here had this or similar problems? I have googled it and alot a people have had this and similar issues, ranging from a defective Leopard disc to aftermarket RAM AND HD's. I used the disc utility function and verified both the permissions and the HD itself, also repairing them, it says the HD's are ok and ready (i have two). I even flashed the drive and tryed with same results. Any Mac wizards out there? If still pretty new to them.