I just got my mid-2010 imac i7 27inch back from the Apple Store today. The first LCD was covered under Apple Care, this one was out of warranty. Both were due to dark spots on the display. After about 10 minutes, three skinny black lines started bouncing all over the top of the screen (sort of like an electron gun inside a TV), and the display jumps and bounces constantly. It is unbearable. I can see the menu bar bouncing at the bottom and the top. The screen will go to sleep, but it will start right up again shortly. It passed the Apple Hardware Test from my OS disc. I made an appointment to take it back to the Genius Bar this week, but this is so frustrating! Any ideas about this? I imagine they will fix it again, but it's a great built-to-order mac, and I still use the older peripherals with it. They gave me a break on some of the LCD cost, but it's worse now.