You may want to consider using one of the custom nvidia tv output tweak programs. I use one with my geforce mx and it works great and has a lot more tweak options than the nvidia driver did. You do need to pick to right program based on the tv output chip that your particular card uses.
Unfortunately some GF4 MX cards used a Nvidia integrated tv output chip and this chip is not supported by these tweak utilities.
Here's a link :
http://tvtool.info/index_e.htm