I've had my macbook aluminum since 2009. Somewhere in 2010, I upgraded to 4Gb of RAM (crucial). Since then, I have a really weird problem. Sometimes, when I put my laptop to sleep or reboot it, it will do the "your memory isn't seated properly", 3 beeps. When this happens I can just hold the power button down and it reboots perfectly fine. There is a 30% likelihood that whenever I reboot/awake my MB, it will 3beep me. I've learned to live with it. Has anyone seen this before? I've reseated the memory several times. it's more of an annoyance that anything, just curious. Could it be that the memory is bad?