If you mean you installed the .run from nvidia, then you need to run the installer again with --uninstall: ./nividia*.run --uninstall and then reinstall the xserver-xorg-core package since the nvidia installer removes the xserver libglx file.
If you mean you installed the .run from nvidia, then you need to run the installer again with --uninstall:
./nividia*.run --uninstall
and then reinstall the xserver-xorg-core package since the nvidia installer removes the xserver libglx file.