Ah, modern life. So dependent on my computer. Hate when it goes weird. So I'm computing along on my Macbook (using a wireless trackball) when all of a sudden the primary click button doesn't work. Must be the trackball...turned it off but the trackpad on the laptop didn't work either. Reboot. Works...for a couple minutes...same problem. Reboot...doesn't help. Spend about an hour fussing with it. Go online (with my iPad since I can't click on anything with the 'puter) looking for similar problems. Learned all about expanding batteries putting pressure on the back of the trackpad, yada, yada. Then I ran across a guy who'd had a bluetooth mouse that was in his briefcase from work that was interfering with his home computer. Wait a minute! I have a bluetooth mouse that I take on trips and I packed it in my backpack in the next room...usually turn it off but I may have just thrown it in there. Sure enough...and something on top of it was pressing the left click button thus interfering with my computer. Duh.