RivaTuner can only react after Windows have logged on, not before. I have that exact same problem as you and that is mainly the reason why I don't use that card anymore! I think that you'll have to get a new bios for your card my friend. What manufacturer is it? XFX, Gainward, Asus or....?
I think that I may need a bios upgrade myself

("contacting XFX customer suppport")