Hi
Amy,
Symptom:-
Upon installing openSUSE, the X system's automatic configuration may have failed to properly configure the graphics correctly. Typically this results in either a black screen upon reboot, or the wrong resolution being displayed on the monitor.
This guide is for all current and supported openSUSE versions up to and including openSUSE-12.1.
Cause
Typically the cause is your graphics are not configured properly. The reason for the misconfiguration can vary, dependant upon your openSUSE version.
Solution
This section provides some guidance on how to sort out your graphic problem. It is recommended one determine their openSUSE version and read up on some practical graphic theory before proceeding to solve their problem.
for more information refer to the below link,
http://en.opensuse.org/SDB:Configuring_graphics_cards
Hope It helps you.