It's my mouse, a Logtech wireless about four years old. The control part is on top of the table and in plain sight of the mouse. What it does is when I try to highlight a line one the screen to copy it sometimes It will only light up half of the line and sometimes after it highlights the line as soon as I let go of the button the line is no longer highlighted. And sometimes when I hit the back button it will go back two or three pages at a time. Could it be the software? The mouse seems to work just fine at everything else.