Out of nowhere a line appeared across my monitor and won't go away. It's a horizontal line about 1/4 of the way up from the bottom of my monitor. I've had this iMac since '09 and haven't had this issue before. I was just sitting here and all of a sudden it appeared. Tried restarting/shutting down and it didn't go away. The line was there during the shut down process also (blue screen) and when you start up the computer. Anyone know how to fix this? Thanks! edit: when I take a screen shot it doesn't show it.