Mikomi 3 Button Mini Optical Mouse AM-...

On an optical mouse, two thngs happen. The light shines out and a sensor reads the reflection almost like a camera image. Try some other surfaces, particularly ones which are not shiny. If that doesn't help, install the mouse on some other computer. If that works, reinstall your drivers on the first computer, removing the old ones as best you can (Control Panel...Device Manager...etc.). If it doesn't work on the other computer, check for any switches on the mouse (that would be uncommon) and for warranty coverage. Otherwise, the light sensor is probably broken and there is little you can do.