Fedora 13 - single pixel for GUI login screen so unable to login to Gnome/Xfce

[Edmon Begoli]

I upgraded from Fedora 12 to Fedora 13 and now, when my computer boots,
I get a login screen but the actual login box with user accounts is a
one pixel wide.

I tried to log in from the other machine, and I found my user accounts
intact but the
graphical login is squeezed-unusable.

Does anyone have any suggestions for this problem?

Thank you,
EB