Vista Gamma Settings

Hey all, I have an issue that I'm hoping or have to believe is not an unusual one. I dual boot Vista and XP, mainly for games and have found that in Vista my in game gamma is horrible. Its normally extremely dark and a lot of games don't have very good gamma control at all. For instance Half Life 2 in game gamma can't be set very bright and so it ends up terribly dark. Unfortunately this is the case with many games in Vista and I was wondering if there was a good way to control this. I have an ASUS GTX 280 and there card comes with a utility called GamersOSD which lets you set gamma in game, however it doesn't work correctly in Vista. Any advice on how to control this would be much appreciated. I have the latest drivers for my card along with the latest GamersOSD release but I still have the same problem.

I have another system with ATI in it and it has as many gamma problems in Vista as nVidia does. This is more a Vista problem than anything else I suspect.