I installed updates and after the restart, the screen comes up black with a blinking cursor. I can get to terminal by ctrl-alt-F1 and sign in, but all attempts to troubleshoot have failed. This is disturbing as this is my development environment and I will lose some progress if I do a fresh install. I am running this in a VirtualBox on a Windows 10 computer. It is a Sony VAIO with 12G RAM, Intel Core i7 2Ghz processor. I have run updates and upgrade through the terminal, then rebooted a few times, but this is not working either. Please help!