Micro's bang on target..
..I just wanted to add that if u disable the nvcpl.dll then the icon for nvida's control panel will not be available ffrom the windows control panel.
Aye29's right that the icon can be disabled from the Nvdia settig's page.
N' as far as the nwiz ... Micro's already explained it .. this is required if u intend using the virtual desktop n' have different wallpapers on each desktop etc.. Also u'll need it if u intend using other nview features like stay on top,transperancy,send to desktop ..etc..
To conclude .. in any case the 2 dll's don't have a big footprint .. so thier memory consuption is not all that great ...U can very well leave 'em enable