New to this site and have a computer problem!

Ok so not so very tech savy...but I am losing my mind!
Every time I click on my mouse - it double clicks. (happens about 90% of the time) For instance, when I click to close an open email, it closes the email then also closes down outlook....aaahhhhhhh! When I choose a site from my favs...it opens and immediatly closes it again.....please help!! (Have checked the mouse settings already! )

 

Its time to buy a new mouse. They're not that expensive, having a spare is always a good idea, and if the new mouse does the same thing then you will know its the system and not the mouses switch. If your short on cash borrow one to test with and post back the results.