I have heard the leopard OEM disc that comes with the computer only works on that specific hardware. I know that means you cannot use a MacBook leopard OEM disc on an iMac or MacBook Pro. What I was wondering is can a new white MacBook that my brother just received be used on an older 2006 BlackBook (I think that is what they're called)? I have an early 2006 model and was curious about this since it is the same specs as my brothers white MacBook. I was't planning on trying this since I like Tiger and have heard Leopard slows the system down a bit, but was just curious about my question since they are like the same hardware.