low graphics mode after 14.04 upgrade

[robertasbalt]

I have upgraded my ubuntu from 13.10 to 14.04 and after upgrade when I start my laptop pops up a table it says "The system is running in low-graphics mode. Your screen,graphics card, and input device settings could not be detected correctly. You will need to configure these yourself. "I tried to do a lot of things from other old post that people suggest how to fix it but nothing that I have tried works.

[kc1di]

What video card does this machine use?
you may need to install drivers for it.

If you don't know which card it is post the output of
lspci | grep VGA

[JonPaul]

same problem. I replaced lightdm with gdm and it came up fine. probably not the best solution but when I posted querying this no one responded....
mdm works too (from noobslab)

during the upgrade there were several files (I can't remember the names) where it asked whether I wanted to keep the original or replace with the new. I suspect I answered wrong on one of these....