Hello
It could be:[br]
1) dead battery/batteries[br]
2) driver not installed[br]
3) usb dongle wasn't recognize properly due to glitch[br]
4) drive for dongle wasn't installed correctly or corrupted for usb port its in[br]
5) dongle radio burnt out[br]
6) mouse radio burnt out[br]
7) you forgot to put usb dongle in usb port.
Try fresh batteries [br]
Try plugging the dongle in another usb port[br]
Try unistalling then reinstalling the driver[br]
Try going in device manager, see if there are unloaded drivers and either remove devices then refresh list; or update drivers.