I own a 1.83 Ghz Core Duo MacBook Pro which I purchased last year in March. Recently (Past Month or 2) when I shut my laptop it doesnt go to sleep like it should. This happens about 60% of the time. This has caused lots of trouble, mostly when I put my computer to sleep and wake up the next morning to find the fans running at full power. I havent had that much trouble with this computer, besides a battery replacement and MagSafe replacement. I have a small whine but it doesn't bother me much. I should probably mention that sometimes when it does manage to go to sleep, when I try to wake it up, the computer doesnt respond and it refuses to wake up. The only way to fix that is to restart it and then when I boot back up it gives me a "Mac OS quit unexpectedly" message. (That happened about 5 times on Saturday)