More info in detail: I have a problem with Excel: When I select any cell, then let go of the left mouse button – it acts as though I am permanently holding down the left mouse button; i.e. it tries to select multiple cells. I cannot de-select the left mouse button and cannot access any of the menu buttons. The only thing I can do is right click on the taskbar at the bottom of the screen and close excel – open it up again and have the same problem! I thought it was a touchpad problem, so tried plugging in my mouse – same problem.