Hi there! My name is David. It’s a pleasure to help you today.
According to what you describe, if the issue occurs even with an external mouse, it is possible that the Click Lock function is enabled.
I can recommend doing the following to check if it is enabled:
Go to Start > type "Control Panel" > inside "Control Panel", at the top right "View by" select "Large Icons" > Click on "Mouse" > Uncheck the option " Turn on Clic Lock" > Click on "Apply" and "OK"
Let me know if the shared information has been helpful. Regards.