In my computer I have Win98 and Win2000. When I use Win2000, I can use the mouse, however, when I use Win98, there's no movement or any sign regarding the mouse. I don't have a clue what's happening. Before, the mouse was ok with both operating systems. Actually I try to re-install Win98, but without a mouse it is almost impossible. I do appreciate with any help in this regard. By taking this opportunity, in Win98, the SCANDISK or DEFRAG is not working properly. It takes forever to run, but still without any result. Any suggestions will be much appreciated.