My desktop computer has been cycling through the number keys by itself, even when I am not touching the keyboard. This has been happening for about a month, and the troubleshooting I have tried so far has not fixed it. What could be causing this, and how can I determine whether the keyboard or the computer is the problem?
3 Answers
This can happen after liquid gets into a keyboard, even if the spill was a while ago. Disconnect it and, if appropriate for that model, clean it carefully using proper keyboard-cleaning instructions. If cleaning does not help, repairing or replacing the keyboard is probably the best option.
The quickest test is to unplug the current keyboard and try a different one. If the number-key loop stops, the original keyboard is likely faulty. If it continues, the problem may be elsewhere on the computer.
It would help to list exactly what you have already tried. Restart the computer, test with another keyboard, and try the suspect keyboard on another computer if possible. Those tests can show whether the issue follows the keyboard or stays with the desktop.

It is a desktop, so I can disconnect the keyboard and test another one.