Anything happen if you tap the screen a few times?
You may want to try a 2 button clear as described here:
http://www.meritgames.com/Support_Center/manuals/Megatouch%20XL%20Technical%20Service%20Manual.pdf· Two Button Clear:
1. Turn game power off.
2. Remove the coin box/bill acceptor.
3. Depress and hold the Calibrate and
Set-up buttons located in the rear of
the coin box opening.
4. With Calibrate and Set-up depressed,
turn game power on.
5. Release Calibrate and Set-up buttons
when “2-Button Clear Detected” is
displayed on screen.
6. “2-Button Clear Complete”
· Using the diagnostics software, run the
“Motherboard Tests,” “Processor Test”
and “Co-Processor Test” to make sure
they are each working correctly