when i press the scroll lock key to turn the sweetfx of and notice the difference between it and the the game's picture. my monitor refresh frequently and turned to window mode the back to full screen mode, make the sweetfx can't be disabled. what should i do?

Sounds like an incompatibility with whatever game you're playing. There really isn't a whole lot you can do. But you can try setting the #define USE_SPLITSCREEN option in your Sweetfx settings to see the difference without having to use scroll lock.

how to know the compatibility of the game with sweetfx?

Maybe your game control settings, is using scroll lock to switch between fullscreen / windowed mode. if that is the case, change that button from the game and try again. Is your game 32bit or 64bit ? or maybe you have an old keyborard, like me. and you need to turn the NumLock off ... or the FLock key, like I do.