I would not recommend you use the noise reduction preprocessing option in VirtualDub, you can get better results if you process after capturing. Set your format, frame rate, levels, and if you're using YUY2 I'd recommend you check both options for extending luma black & white points.

For post-processing, you'll probably want IVTC, maybe some sort of colour adjustment using levels or HSV adjust, and perhaps some noise reduction (smoother). To be honest, I'm not really up on the latest options in VDub, I switched to using AviSynth years ago which is much more powerful.