This iMac is about 6 months old. It has 2 very annoying traits, when reading a page it will revert to the previous page and it also keeps scrolling to the top of any page particularly when typing messages such as this. Neither fault happens with MacBook or iPad so I assume it is not the router or airport. I know I should return it to a store but lugging a 27" is no a good thing fopr an old guy like me. Apple care had no previous experience with this problem.