I have a Dimension 4700 that was purchased in Jan 2005. I do not have a wireless. While working, the mouse will suddenly jump, either to the right or left out of sight, and I have to manually move it back. It is very random and I have not seen a pattern that I can track. I checked my mouse pad to be sure I have nothing on it. And it is the original Dell mousepad that came with my system. My biggest concern is that I have gotten a virus or something. Any help would be appreciated.