Samsung SyncMaster 906BW Owner's Manual page 39

If there is no image on the screen or a "Not Optimum Mode", "Recommended Mode 1440 X 900 60
Hz" message comes up, disconnect the cable from the computer while the monitor is still powered on.
If there is a message coming up on the screen or if the screen goes white, this means the monitor
is in working condition.
In this case, check the computer for trouble.