Try copying all your user data to a new profile. Is your left-click working again? If so, your primary user account has probably become corrupted. The app will ask you for the new user's sign-in details and name. Make a temporary new local account by navigating to Start > Settings > Accounts > Family and Other Users> Add Someone Else to This PC.
You need to establish whether the problem is unique to your user account or a system-wide issue.
