You receive a "RUNDLL Error loading irprops.cpl" error message when you start Windows XP

When you start a computer that runs Microsoft Windows XP Professional or Windows XP Home Edition, you may receive the following error message:

This problem may occur if any of the following conditions are true:

• The Bluetooth Authentication agent is installed in your computer, but a DLL file is missing.
• The Bluetooth Authentication agent was removed from your computer, but its registry value still exists in the registry.

To resolve this problem, use the following methods in the order that they are presented.

Remove the Bluetooth Authentication agent

To remove the Bluetooth Authentication agent, follow these steps:

1. Click Start, point to Settings, click Control Panel, and then double-click Add/Remove Programs.
2. On the Install/Uninstall tab, click Bluetooth Authentication Agent, and then click Add/Remove.
3. Restart the computer

Delete the BluetoothAuthenticationAgent entry from the Windows registry

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

If the Bluetooth Authentication Agent was removed from the computer, follow these steps to delete the BluetoothAuthenticationAgent entry from the Windows registry. To do so, follow these steps:

1. Click Start, click Run, type regedit in the Open box, and then click OK
2. Locate and then click the following registry key:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
3. In the right pane, right-click BluetoothAuthenticationAgent, and then click Delete.
4. Click Close to close Registry Editor.
5. Restart the computer.