There is a distinct cracking or clicking sound coming from the back of my iMac, I have the July 2010 model with 4GB RAM, and Intel Core i3 3.06GHz. I have had this computer for a year now almost exactly and the warranty runs out on the 26th of January. For some time now I have noticed that coming from the back of the iMac there is a cracking sound. I have searched the internet and found a lot of talk about a "clicking" sound coming from the back and while it occurs the spinning beachball appears. However, the sound seems to me more of a cracking sound and the beachball doesn't appear. I leave my computer on for days on end, sometimes weeks and the screen does get a bit hot, could it just be that the screen is expanding from the heat and I'm being too careful? What really gets me is that I've also had a kernel panic this week and just today I left my computer on for an hour and when I came back no bluetooth devices would connect to my black screened iMac and I was forced to shut it down. When I turned it back on it said that it was shut down due to an error. I read up about kernel panics and healthy computers should only get them once a year if that and I'm not sure if I had another kernel panic today. What should I do? Should I backup my data and take it into Apple or is the cracking sound nothing and the kernel panics "normal"?