Toshiba laptop keys not working

[lisa206]

Hello,
keyboard is not working. when keys are pressed they either do not work, wrong character is showing or more than one character is there

 

[AntiZig]

Hello, your problem is likely caused by one of the following:
driver problem
keyboard hardware issue
motherboard hardware issue

 

[Starcase6]

I don't have an answer but needed to ask Antizig how to address those possible solutions. How would I test to see which one is affected (if any of the three are the culprit)?
Thank you for your assistance.