A very strange answer Paulie D!!
I have a Microsoft cordless mouse (the same model), which a few days ago developed a "varied number of clicks required to do anything and move on" fault. I plugged in a USB mouse...same thing. So it's the computer and possibly a virus?!!!! Oh NO!!
A VERY annoying problem as it has taken hours to surf the net and do things that should have taken at least a quarter of the time. A worrying problem because something is obviously wrong with the computer, and no virus or spyware program has picked it up.
ANSWER: Do as has been suggested!! Remove one of the batteries (only one appears to be able to be removed, and not the one furthest from the lens). For the past hour I have one clicked my way around the net without a problem. Can anyone explain? I'm using rechargable batteries? Thanks for the answer...I'm HAPPY!!