I have a brand-new EliteBook 840 running Windows 10. The left touchpad button sometimes works and sometimes doesn't. It's like this: If I click a second time (or a third time) with the left button, without having moved the cursor (not double click, but two separated clicks), then the computer doesn't respond to the click.
If I click by tapping on the touchpad area (instead of pressing the button) then everything is fine. But I don't like tapping!
If I click with an external mouse connected via USB then everything is fine.
If I move the cursor and then click, then it works.
The problem is very annoying because each time the computer doesn't respond to the clicks, I have to move the cursor and then click again.