Curser jumping around

I am in desperate need of computer help. My curser jumps all over the page. When I am typing it will jump to where ever the curser is located. And I start typing in letters that don't belong there. I don't think it is the wireless mouse because it does it when I am not using the wireless mouse. The Mouse is a Microsoft. It also when I type a letter sometimes it will close the window completely and the web site down. Any advise would be apprecited. Thanks