My brothers mouse has mysteriously stopped working for no apparent reason, he can use all the buttons on it such as back, forwards, left click and right click but he is unable to move the mouse and get a response from his cursor on screen. It's as if the mouse isn't plugged in it doesn't react at all. We have already tried unplugging the device and plugging it back in but no luck. Also this happened as he was using it and the mouse hasn't been damaged as far as I'm aware.
Sounds like the LED or laser may have gotten clogged with dust, or has just died. If it is one of those optical mice with the 'red' LED light underneath it, does it light up? Many mine these days no longer have an LED so the absense of a light underneath may not be a problem.