I bought the new imac 27" 2.7ghz intel i5 quad core, 4gb ram,ATI AMD Radeon HD 6770M 512MB ram. 1TB HDD. i run windows 7 ultimate 64bit on Bootcamp earlier When i bought the imac i ran games such as League of Legends , Twelve sky2, Dead space 2, Deus Ex: Human revolution , Medal of Honor ,crysis 2 etc now since i bought the imac everything ran perfectly the initial month or so but now since last 10 days every 20-25mins since i run these games the display just crashes it goes black with vertical lines and doesn't recover i have to shut down the computer from the power switch. I can hear the games still run in the background so but the display is totally gone. This problem also occurs when i use the software "Maya". i tried reinstalling windows 7 still having the same problem sm1 kindly help me on this.