First go to console (ALT+F2 then type
gnome-terminal). Inside the console type nvidia and press the TAB button. If you have the nvidia drivers correctly install there should appear several nvidia files (Like nvidia-settings, nvidia-xconfig, etc..)
nvidia-xconfig so it edits the xorg.conf file with the nvidia configs. Reboot the PC.
If you can not still have special effects then do the following:
- Install mesa-utils (
sudo aptitude install mesa-utils or
sudo apt-get install mesa-utils)
glxinfo | grep "direct rendering". If a NO appears then there is some problem with your nvidia installs. If a YES appears then typing
compiz --replace after pressing ALT+F2 should give you the 3D effects.
If the NO appeared just try to reinstall the drivers with
sudo aptitude reinstall
dmesg | grep "nvidia" in console to see if there is an output regarding nvidia. Normally the output will say how to fix it.