Re: After Upgrade its failed to bootup
Do you have a/any liveCD available (probably the old 8.10)? If yes, boot into it and go live session (aka TRY UBUNTU WITHOUT ANY CHANGES). Once in live session, go to PLACES (top left of the desktop) and access your "sensitive" files from there. Copy/paste/drag them to a thumb drive.
About your boot problem ... did you/have you entered SET-UP and loaded the defaults as mentioned by the error message?
"The key to everything is patience. You get the chicken by hatching the egg, not by smashing it" .... A. Glasow