how to get lights off the screen when problem is repaired

Try clearing code with scan tool, check if there is any additional codes, also you could try driving the car normally, and after about 80to a 100 miles or so it should go away. If not last but not least try disconnecting your negative battery terminal, leave it off for about 40 minutes. Good luck.

What can we do if no scan tool is available??

Try unhooking the battery for a few minutes to let the computer reset then hook it back up to see if that fixes it.