I don't have an NVidia, but I can see how that would be annoying. Things like that frankly bug the heck out of me -- it seems like overkill to get their name on everything, and I would be bothered by a logo like that as well.
Anyway, I did some Google searching for you, and came up with a utility called
NVmax, which allows you to tweak the NVidia and supposedly has an option to remove the logo from the corner of your screen. I found about it about it in this
forum.
I can't vouch for this software though. It's just a possible solution to your problem which I ran into.
