I was trying to play League of Legends using my Graphics Card (have everything listed here installed), but the card was not being used. Then, I installed lib32-nvidia-libgl (removing lib32-mesa-libgl in the process) and rebooted, and then the games just stopped opening at all. I opened Playonlinux and it said that I had missing Opengl libraries. I switched back to lib32-mesa-libgl but now "nvidia-smi" shows this message:
NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.
I didn't try to purge the programs before reinstalling.