Sinumerik 810D

Hello

When we start up the machine, it only want to reboot all the time. We got this message first ERROR: Unable to control A20 line! XMS Driver not installed.
this is followed by. Warning: the high memory area (HMA) is not available, additional low memory (below 640k) will be used instead. After this it says you are supposed to push the "." button and after that another screen comes up saying that The register might be damage press "-" button to restart from last good point. if you are not quick enough a big screen comes up that says its safe to reboot or restart the system.

How can we start the system again because we have pushed the minus button and the dot button but it only want to restart with the same error message again.

Hello,
Which is CCU? Can you attach the snap of main CCU / 7 segment display? What is the value displayed on 7 segment LED?

Try plugging in a USB keyboard and doing it