Hello. I wanted to upgrade my Core Duo 2Ghz Processor with T7400 Core 2 Duo T7400. But mistakenly, I tried to pull out Ati X1600 with Screwdriver. When I realized its not the CPU, I stopped my attempt. It looks like there is no damage. Found real CPU & perfectly replaced it with C2D T7400. Anyway, When I finish my job & open iMac, screen became dizzy. My Hard Drive have 3 partitions: 1st partition is empty, 200GB: Ready for install mac os x leopard. 2nd holds my personal files: 700GB. Last one holds Windows 7 OS. So, I tried to boot from Snow Leopard Disc but dizzy screen eventually become very bad which I couldn't do anything. Later, I tried to open Win partition. But when I try this system restarts. I Also tried win 7 CD boot, which gave me only black screen. I reopened inside of my imac, pulled out new cpu & placed old one. Also checked any anormalities. When I finish the job & open the system, nothing changed. I think somehow I killed my graphic card. Any suggestions would be very good.