With normal conditions, it would take a long period of time to manually pair the Keyboard & mouse because you need to use buttons on screen to login. Furthermore, manually pairing steps are much harder than the way below.
The above symptom may occur on the following system:
Do the pairing before the PC is on, before login to Windows
1. Turn on your PC
2. Press and hold the Signal button on your Keyboard on the left side, see Fig.1.
3. Wait a moment, you will see the blinking light on top, see Fig.2.
4. Press and hold the Connect button on the bottom of your Mouse, see Fig.3.
5. You will see blinking light at front/top of your mouse. Press the signal button behind the stand, see Fig.4.
Your pc will automatically search and sync I/O bluetooth device, and there will be a dialog box appear, requiring to enter the pin code from your keyboard (Fig.5)
6. Pairing successful - Message will appear: "Wireless keyboard and mouse paired with this computer".
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