Get your wireless keyboard and mouse working

Check all of the cables are plugged in: obvious, but try it.
Replace the batteries in the keyboard and/or mouse.
Reconnect the devices by pressing the reconnect button on the wireless receiver, and on the keyboard and mouse. Failing to reconnect wireless devices after changing the batteries is the most common cause of wireless keyboard and mouse failures.
If nothing is working still, restart your computer. If your computer does not have a reset button, then you can shut down your computer by pressing the power button. If the machine still refuses to shut down, try pressing and hold the power button for 10 seconds.
If this didn’t fix the problem, try plugging in another keyboard and mouse that works on another computer. If the problem persists, then something is wrong with your computer and it should be serviced by an engineer. Otherwise, your keyboard and mouse are faulty.
If the keyboard and mouse work erratically, then you may be suffering from interference from another device. It is possible for another wireless keyboard, video sender or garage door remote to interfere with the signal from your keyboard. Try reconnecting the keyboard and mouse again, or locate the source of the interference. If all else fails, replace with a wired equivalent.