Hi guys, I have a Core Duo black Macbook, currently running Leopard. But the problem below also happened in Tiger. Sometimes my mac would just freeze, nothing will happen. If I click on the trackpad (after a few seconds), the mac will restart. Every now and then it might not even boot up. I did go to the Apple Store, the guy said he re-set (as in, take out and put it back in), and seemed to fix the problem, he also recommended upgrading to Leopard and do a Erase and Install, which I did. But I still get the problem. I'm thinking it might be a RAM problem, what's the best way to check if I have a fault with my RAM? Thanks.