I have a 2.2 15.4" MBP which will not sleep upon closure of the lid as of today. I just picked it up today from the Apple store where the full top was replaced due to a display problem. Searching here and on other forums, I found a number of people with this symptom, but with different causes. The computer sleeps normally when set from the apple menu. I tried resetting the PRAM. no change. I ran a small magnet along the right side of the screen with no effect. When I run the magnet down the right side of the computer, the computer sleeps when the magnet passes around the bottom of the speaker grill and awakens when I remove the magnet. It would seem that the sensor in the base is functioning. Is the top only a magnet? How likely that there could be no magnet or a misaligned magnet in the the top panel? Compounding the issue is that I had replaced the hard drive after I bought the computer, so when I returned it for service I put the original back in. When I picked up the computer I turned it on and off to check it out. Then I reinstalled the larger drive. It was only after this that I experienced the sleep issue, however I never tested the sleep when I picked it up from the store. My thought is that since running the magnet along the bottom case causes the computer to sleep that my opening the case for the hard drive exchange isn't the problem, unless it's possible that the reed can move in the bottom case and is misaligned there. The apple store is an hour away and I leave for a trip on Saturday, making this a potentially frustrating experience. Any ideas? thank you in advance.