|Trying yet another mouse would be worthwhile because from your first try this seems to point to something more global which affects both mouse and touchpad. |
#6 would be worth a try too. If that fails go back to Device Manager and let us know if there are any errors showing there, particularly under the headings "Keyboards" and "Mice and other pointing Devices" - errors usually show as yellow exclamation marks.
Did this fault just suddenly arise out of the blue or was it after you did something?
Always pop back and let us know the outcome - thanks