Scott, I suppose 'no problem' is not much help, but on my system, Vista Home Premium, ATI 1650 GPU and latest driver, the brightness slider works as it should as well as the enhance contrast checkbox in 2D mode. In 3D mode, the slider does not have an effect. (That would be nice!) I cannot produce a dark gray shade however with the slider; it's aways some degree of white as I would expect.
Larry