Fedup 20 to 21 - Gnome fails to start

[linuxnutster at videotron.ca]

I used fedup to move from F20 to F21 on two PCs. Both have Asus EN210 
Nvidia graphics cards. In both cases, starting gnome would result in an 
error which reads " a problem has occured and the system can't recover." 
I reinstalled the akmod nvidia driver on the PC with an EN210 1GB card, 
and, voila, the problem was solved; however, this did not work for the 
PC with the EN210 512MB card. I tried a few methods of reinstalling the 
driver, including negativo17 method ( 
http://negativo17.org/nvidia-driver/ ) with no success.

I am not a linux expert, and would appreciate a few suggestions. I also 
tried suggestions here:

https://ask.fedoraproject.org/en/question/56816/gnome-fails-to-start-after-fedup-to-fedora-21-beta/ 


http://forums.fedoraforum.org/showthread.php?t=204752

I also tried the suggestion in the second link regarding enabling 
"updates testing" ( newer kernel, etc.. ) with no success