You should revert back to the older set of drivers for your card, and do the profile for the game as suggested above in order to force this Frankenstein's monster of a modded 15 year old game to work, you might lose a few frames in quake but i dunno what else to tell u. This has zero to do with bootleg and everything to do with your computer's hardware. You might just as well be posting in the Nvidia forum.
Edit: meh, sorry clicked through the new post warning. So lemme look and see if I have any helpful suggestions from here.
first thing I would try is make sure you set profile for the correct executable... idk I use the bootleg bat file that it makes a desktop shortcut to not sure how the profile works exactly.
failing that, if you are sure that your nvidia card is actually being used to run the game, start turning off things in the bootloader config, first the safe mode of the movie player, then shaders. but all the mods should run np on your card, I think the profile isn't set but not positive by any means.