It seems that Microsoft Windows XP has a problem with pin-less Apple devices.

I hate cables and wires all around me, so I’ve decided to switch to a bluetooth mouse and keyboard.

The problem arose when I was trying to pair the devices with WinXP, because the pin-box was empty:

The problem can be observed as an empty pin-box. After googling around and trying various things, this scenario worked for me to fix the problem:

• Go to Registry editor (regedit)
• Go to HKEY_CURRENT_USER\Software\Widcomm\BtConfig\General key
• Set the “PinCodeWord” value to a decimal value 1111
• Set the “UseFixedPin” value to 1
• Restart your bluetooth device (usually by your function keys or other methods)
• Go to “add new bluetooth device”
• Type 1111 on your laptop keyboard
• Press enter on your bluetooth keyboard (or on your laptop keyboard if you are pairing a mouse)

It should work, if not, be sure that you have restarted your bluetooth device.

Note:  Remember to change the values back in the registry, as they will cause problems while pairing normal pin-devices.