My early 2009 20" iMac 2.66 has suddenly stopped working. When I turn it on it makes some funny noises, and I get a loud fan noise for about a minute or two. It boots up, and the dock appears after about 5 minutes, but the top menu bar doesn't. Then nothing happens, I can't open a finder window or nothing. I just get a coloured spinning wheel for about 10mins, and nothing happens. Is the hard drive dead? Or might it be something else?