Close the emulator and restart
EDIT : Anyway you don't need OpenGL to play this game
i did that and opengl still made it crash and the reason i wanted to use opengl is because i heard it would make the graphics better for this game as the gfx are blurry for it on dolphin

Settings?
Where did your hear this?
what game?
Monster Hunter 3 [PAL] is on dolphin blurry
the NTSC Version of the game works fine