Inspiron n5050 - Touchpad Stuck?

On my Inspiron n5050 laptop, I always use the touchpad, which, as you may know, includes only a right and a left click button. Despite this, occasionally my laptop acts as if a mouse's center button - the scroller - is stuck down. When this happens, right-clicking is entirely disabled and the left-click functions are almost entirely unavailable. Both left-clicking and right-clicking once will both bring up a scolling, four-arrows icon. On Google Chrome, left-clicking will not open a new tab, but using either button to click an existing tab will close it. And left-clicking will not open the Windows Start menu - I can only perform actions on the start menu if I know the keyboard shortcut. Restarting does not fix the problem.

I'm sure this is a simple fix and I'm just accidentally clicking something I'm not supposed to. But I've had this laptop for nearly two years and this has never happened before - now it's happened twice in one week. I'm hoping someone can tell me the actual fix to this, because the frenzied clicking-every-button-I-can method I employ seems to be a hit-and-miss. Any suggestions?