First of all, I know NOTHING about desktop specs. I know laptops, but not desktop. So please help me out. Ok, the games I play are Battlefield 3, CoD series, and other modern games. Mostly shooter. Also the monitor, I heard desktop monitors weaken your eyes a lot because it's really bright. So a 17 to 24 inch monitor, that's really easy on your eyes. OS is not needed, my school provides me with free Windows 7 or 8. I play games like 2 or 3 hours a day, so a good cooling system is also needed. Thanks a lot, I really don't know anything about motherboards, and that stuff.