I had Ubuntu 14.04 for a few weeks, then today when I turned on my PC it prompted me to update to 14.10. After downloading and installing everything, it told me to restart my computer. It turned off and turned back off, but the screen never displayed anything. The computer is on but it won't display, it just says "no signal". What can I do to fix this?
Try to replace vga card
Check data cable
If you got a signal from your screen, boot in rescue mode and check your system.
I changed the greeter and it worked. I think it was a problem with the X.Org drivers.