Hi ptfe, thanks for helping me:
Iwas using Ktext and Kedit, but they didin't let me save the file. The only way I found to edit this file was writing x86fcfg int the root. It let me change the drive to nvidia in a window that open when I do this command. However, I didn't see anything about open configuration and the games are very slow. writing w86config nothing happens. Please how is the best way to edit this file, step by step because I've just started in Linux World.