It's definately a driver issue - You can use the add/remove programs for the drivers aswell as device manager but they still leave little bits all over the place and these can cause problems - hence what you have - from now on whenever you install the new drivers use that DRIVER CLEANER to do is as you will get a COMPLETE removal.
you are better off just checking that the ones in the C:/NVIDIA are gone, its if there is more than one in that location you can have major issues.
as for us helping - thats what we are here for :)
Oh by the way I checked and there should be 2 6 pin cables going into the GPU