While it’s possible that an A20 error could apply to something else, it’s very unlikely.
A20 Errors
The A20 error displays during the Power On Self Test (POST) process very soon after the computer is first started. The operating system has not yet loaded when this error message appears. The error message may appear in many ways, but these are the most common:
A20Error A20A20 Error
How to Fix the A20 Error
More Information on the A20 Error
Some computers may let out a sequence of noises to indicate an error. These are called beep codes. See How to Troubleshoot Beep Codes if you need help finding the BIOS manufacturer and/or help to understand what the beep codes mean. To do this, first remove any dust or debris from the end where you see the pins. Then, with a paperclip or something else, like a pen, bend the connector pins to the point that they look straight again. If you’re still having troubles at this point, make sure the PS/2 port is clean and wiggle the connection around as you press it in. It’s possible you may end up bending a pin just right so that the cable will connect correctly. It’s also possible to identify the A20 error through a POST code using a POST test card.
