thank and a screen problem

[terry]

Thank you for helping me with my root password. I now have root.
I used a f12 dvd as a rescue cd to do it. the upgrade one. it only gave 
me  a 800x600 screen resolution. that didn't bother me until I used the 
dvd to upgrade my f11 to f12. Now it bothers me for I still have the 
same resolution.  going into the display area of system, I cannot change 
the resolution. Any suggestions, please.