I just bought a brand new 21.5 inch iMac 3 hours ago and it won't recognize my Apple 24 inch Cinema Display. I was been using the cinema display with my laptop for 20+ months now and it still works with my laptop, but this brand new iMac wont use it as an external monitor. I keep hitting "Detect Displays" but nothing happens. Did all software updates that were available through the Software Update app, restarted, shutdown, unplugged the monitor and plugged back in, nothing is making it work. Please help. This is very frustrating for a brand new iMac right out of the box to not work properly.