PCIE x1 tandem GTX560

Ok so to achieve my three monitors i want on my games i have decided to place a pcie x1 card in my current system as it doesnt support sli or crossfire
Once i put my x1 card in it installed the drivers like it should
then after it installed the drivers i restarted as you do
once it booted again it had found this new 8400 GS with my third monitor attached but there was no image on screen and after fiddling around with different settings im stumped as to why it isnt showing on screen other then my adaptor and ive checked that the graphics card and screen are connected properly
i still have no idea
any ideas on how to fix it would be appreciated