back to gnome ubuntu
 

when i play a game sometime it stuck
and from what i was reading i should do ctrl+alt+f2
and kill the process
but how do i get back to the gnome?

I think it's ctrl+alt+f7.

Some people seem to have had problems with that with Ubuntu in the past:
https://www.google.co.uk/#q=ctrl%2Balt%2Bf7

ok thx it work