I was using Firefox just now to post this question and the mouse cursor started jumping all over the screen and opening and closing different web sites. So now I have to use Internet Explorer to enter the same question again. Over a week ago I allowed the newest version of Firefox to load. Since then, whenever I go on the web using Firefox, in the middle of something the mouse cursor will start jumping around and open and close different web sites, and sometimes close Firefox. I don't even have to be operating the mouse. Most times though the mouse will just go crazy flying all over, and I can only stop it by turning off the modem so that I can get off of the internet. The PS2 Intellimouse operates normally when using IE on the internet, or just playing video games or other regular computer operations. The mouse driver is new and so is the mouse. The problem only happens with Firefox, when I'm on-line.