Hello, I have a Vostro 1500. I am not sure if this is the computer or the optical mouse, or a conflict between the two! I have a Dell optical mouse (came with old Dell computer system). When I am using the mouse pad on the Vostro laptop, the curser does not jump around, and seems to stay where it is supposed to be. When, the usb mouse is connected, the curser will start where I click, but then if the mouse "line" is not kept right with where the curser is, then the mouse "clicks" on it's own, and many things can happen - text gets selected and deleted, the page will start scrolling, etc. Any ideas as to why this may happen? As I was typing this post, without the mouse plugged in, I put the "mouse line" up by the "title", and kept typing my post here. The screen as adjusted 4 times - automatic scrolling! And, at one point, the computer went back 3 screens from where I was typing! It is like the "mouse line" went up to the back button (all on it's own), and clicked the back button! I was able to get back to this screen by hitting the right (forward) arrow button. Any ideas? Thank you for all of the help!