I have a 2009 iMac that runs pretty well perfectly...except for a problem that has recently started to happen when I put it to sleep. I had noticed that on odd occasions it would wake up just a few seconds after going to sleep but there seemed to be no reason for this. Today I realised that there is a definate pattern to this. I put it to sleep, then I get up from my desk. When I turn my office chair and lift myself off it, the Mac wakes up...every time! It happens just as I lift myself from the chair, turning to leave the desk. If I put it to sleep while I am standing there, nothing happens. Turning the chair with no one in it is fine too. This has only started to happen in the past couple of months. I can't see anything that has changed in that time. The only other times the iMac has switched itself back on is when I switch off the desk light RIGHT AFTER putting the mac to sleep, that also fires it back up. I thought that was weird enough but this is really nuts. Anyone have a clue as to what is happening?