>Is your mouse a simple one with 2 buttons and a wheel, or does it have a lot of extra buttons? Sometimes extra buttons are programmed by default to do certain actions, one of which could very well be "search". Maybe you are inadvertently pressing such a button when you move the mouse to the top right? Or, the button may be too sensitive, or maybe it's stuck or broken so it's making contact when it shouldn't be.

It is a Logitech, with two buttons and a mouse wheel in the top middle. Now that you mention it, I see there is a search option on top of the mouse. Clicking on it launches the Windows Search. There you go. Thanks