Imac graphic

I have 1 question for you.

I use late 2012 27" iMac(model name : MD095KH/A---Korea)

so,

Q1, In the bootcamp(windows 7) I use adobe premiere pro and adobe after effects. I use these program about 2~3 hours, My iMac display pixels was broken.

and, display was so hot.... Can you tell me why my iMac display pixels broken? and why display is so hot??????????