Unplug the larger monitor. Then, on your Dell, go to "Start, Control Panel, and Power Options".......set your monitor to never go to sleep. Shut down, and plug back in your auxillary monitor and turn it on. If that still won't work, try a combo of key strokes by using "ALT+F8" to illuminate the monitor.
Thank you for your suggestions also - will do them too since I do NOT want the monitor to go back to sleep.
Now here is the thing - my big monitor is now AWAKE but the laptop screen apparently has now gone to sleep!!!
(I don’t need it now - but when I ever want to take the laptop with me I will - so what do I do to get that screen back working again??)