WMC is already output video limited levels. That's why if you set PC level, you will get the best PQ on your PC (assume your TV is set to receive video limited). If you set your CCC to convert to video limited, you get double conversion and that will never work right. In general, I'd leave off any such conversion in the video card driver.
If WMC is all you use, you are all set.
If you use other players, that's a different story. WMP for example, only output PC range video. So, in your current setting, you will get black and white crush.