How about other USB devices? Can they work?
Next, did it prompt you something like "If you want to keep it working, unplug and plug in again." Then you press OK or Cancel? If you press OK, unplug and plug in again, your USB mouse would work. If you press Cancel and continue working, next time you plug in your USB mouse, the mouse would be officially declared dead.
Lastly, check that the piece of plastic in your USB ports are in. Without that piece of plastic, USB devices won't work. All USB ports must have that piece of plastic, any USB ports that doesn't have will stop all USB ports from working as USB ports share the same IRQ.
