So I got a used macbook for christmas that doesn't have lion on it. Rather it has snow leopard. I was thinking of getting it up to date on the OS but I was wondering if I should completely back it up first? I am new to the mac community so I just wanted to make sure... My specs are: Intel Core 2 duo 2.4Ghz, 2GB 1063MHz DDR3 RAM, 13" screen, 250Gb HDD. Its the latest model of the plastic macbook before they stopped selling them.