Too dark with my Nvidia Riva Tnt2 M64

My Nvidia Riva TNT2 M64 card runs fine on everything but OpenGL.I have been trying for ages to find a solution but have found none to date.All I know is that it is a problem with the card & no-one knows how to fix it- i thought maybe I could change the OpenGL settings or something(anything!)

Have tried everything else - monitor, application etc…!