Today I was trying to get tap to click to work on my ACer c720 with only ubuntu installed. At one point I restarted the computer and I only got a black screen with a non-blinkning cursor in the top left. I don't get a login screen and I can't change to tty1 or anything else once this happens. If I time pressing esc just right I can get to tty1 and from there I can login and switch to any workstation I want. From here I tried uninstalling and reinstalling unity but that didn't help. When I try launching unity from the tty1 I get a compiz (core) - fatal: couldn't open display :0. I deleted the XAuthority file in my home folder and that didn't help. The only file that I think I changed was /usr/share/X11/xorg.conf.d/50-synaptics.conf.