Hello, Luznarr
Welcome to the Microsoft Community.
Thank you very much for your feedback. I have carefully read the information and problem description you provided. You mentioned that the left button on your computer is no longer available.
According to your problem description, if it is a driver problem, your current situation should be that both the left and right buttons are no longer available. If your right button can still be used, it means that some hardware failure may have caused this problem. I have no other better suggestions for you. I suggest that you need to contact the technical support personnel of the device manufacturer or the personnel of the nearby computer repair shop. They will provide you with more professional tools and methods to help you solve potential hardware problems and provide you with more useful information.
Best regards
Brian - Microsoft Community Support Specialist