This How To I stumbled upon trying to fix an x crash after an kernel upgrade. The log file showed that the nvidia kernel was the problem.

I exited the blue x log report and logged in at the command line.

I guessed that Envy might run so I gave it a go. No immediate luck but it did look possible. It prompted for one of two switches -t or -g. The -t switch was to start Envy in text mode whilst the -g was to start it in GUI mode.

I entered

sudo envy -t

nd got a text version of the Envy screen and was able to deal with the Nvidia problem. One option allowed to retry booting x again.

This worked like a charm and should be publicised; hence this How To