I had a fresh install of 13.10. The graphics were laggy and it was crashing when I was changing wallpapers so I went ahead to install the latest Nnvidia drivers. (it was using some generic one before that).
I followed a tutorial that had me add a PPA rep and install it from there. All went good but, when I restarted; Ubuntu doesn't load but gives me a blank black screen after I select it from the boot menu.
P.S.
Here is the tutorial I followed.