After using my MacBook for about 15 min, it starts to get very hot. Is this normal or should I take it in? It is almost 2 years old, I have Leopard 10.5.8, and this has just started about a month ago. I do have the extended warranty on it, so I know it doesn't hurt to make an appt at the Genius Bar, but I wanted to hear from you if I should go down there or not waste anyone's time! Thanks everyone!