Q: system locked while upgrading from 14.04 to 15.10 I started the process of upgrading from 14.04 to 15.10. after about an hour of the update doing its thing, a window came up that asked if I wanted to replace a gnome file. my intent was to agree, but the whole system was locked. pointer wouldn't move, no keyboard commands worked, nothing. so with great reluctance I did a hard reboot. now the system wont load. I apologize for the lack of details on the file that was to be replaced. what is my next step?  
Edit: After some contemplation, I found that I can boot into recovery mode. My thought is that I could restart the upgrade from the recovery terminal. However, I have no idea what command to enter. Will do some research, but help is welcome.
