Ah, I thought you were using the games inbuilt screen capture app.. As I'm sure your aware many games have a key that when pressed takes a screenshot (usually F12 but it can be anything) and I thought you were getting blank shots from that..lol. Oh well, anyway you won't be able to capture screenshots using Prt Sc because it's not designed to do that. As icky and cybercore suggest you need either Fraps or xfire..