GNOME - Screen is all messed up

[Matrix64]

Hey,
I just installed RHL 7.0 When I log in to either GNOME, or KDE the screen gets all messed up, but then I work it out just by clickin around. Im wonderin if I didnt select the right monitor or screen resolution. If so, how would I change that. I am very new to Linux and I am just learning my way around.
Thanks.

 

[mbaranski]

to get a command prompt at the login screen, press:

ctrl+alt+F3

this will allow you to log in as root an run XF86config (i think that's what is called), then do :
reboot

and see what happens.
Disclaimer:
Beware: Studies have shown that research causes cancer in lab rats.