One morning about a week ago I logged into my Mac to see this red line down the the length of the display and it's been there ever since. I've tried rebooting and resetting the SMC controller etc and it's still there. I've taken screenshots of the affected area and the line isn't there which leads me to believe it's not the graphics card but the display itself. Anyone seen this before? Really pretty poor quality from Apple recently. This iMac is a Mid 2010 so it's just barely 3 and a half years old. A little soon for a display to start dying if you ask me.