Right after I downloaded the newest driver for my nVida GeForce 5950 FX GFX card,(ver 6.14.0010.6177english) Vendetta doesnt even start, it just goes to the starting screen then instead of the main menu coming up the screen just starts flashing.

Sounds like a problem with your drivers, not with Vendetta. It wasn't doing this before you installed the new drivers?

Well, my other games (Counterstrike Source)need that driver.

I am using this driver myself, but with a TI 4200.
Try reinstalling directx, if this doesen't help rename the config.ini in the vendetta directory, so vendetta starts with default values again.