Are you trying to run a Multifocal ERG but the stimulus does not appear on the screen?
Chances are that your screen is either on but not reading a signal, off, or telling you that "video mode is not supported". Here are a few things to try:
Press the Monitor's Buttons
There is a column of buttons in the back, left of the monitor.
Adjust the Software
Close the current protocol and switch to a different protocol, like a Pattern VEP.
Close the software and reopen the Multifocal protocol.
Check The Connection
Unplug and replug the DVI cable from behind the monitor while the software is off.