I recently bought an used iMac (was purchased new in feburary 2009) in which I knew the screen was not showing any video when I bought it. ( I was okay with that I thought I'd give it a go at fixing) well the problem seems to be within the LCD itself. When I hit the power button I hear the chime, fan spins, and the hard drive does it's thing. I ended up taking the casing off the iMac to where it only shows the bottom half of the insides underneath the LCD. My question is now to diagnose what exactly is wrong with it by using the 4 led lights. I have searched the forums and the Internet up and down for which ones mean what but I have only found out information on older iMacs. When my iMac is off (still plugged in) LED 1 is on. When I turn the iMac on LED 1,2, and 3 are green. Which that leaves the 4th LED not being lit up at all. I suspect this has something to do with the iMac not showing any video but as I said I am not sure because I cannot find any information on it anywhere. Any information would so helpful and I thank all you for your time.