There are some troubleshooting steps, that you can try:-
- Remove the batteries from your keyboard and wait for few seconds and then check if its working or not.
- Unplug your wireless adapter from the USB port and plug it again and then check again
- Go to the Device Manager, under the keyboards, try to update the drivers or you can uninstall and reinstall the drivers for the keyboard
- Try to use the different USB port for the wireless adapter.
- Restart your computer once and then check if your keyboard is working