Make sure you have the latest Windows service pack installed. You can obtain it from the Microsoft web site.

Make sure the Bluetooth adapter is attached properly.

Ensure that your Bluetooth adapter uses the Microsoft Bluetooth stack. If you have installed Bluetooth adapter driver from the manufacturer of the Bluetooth device, it is necessary to uninstall it, reboot your computer and allow Windows to install standard drivers from Microsoft.

Related links (from the Microsoft web site):

• How to install and configure Bluetooth devices in Windows XP Service Pack 2
• List of Bluetooth radio drivers that are included in Windows XP SP2
• How to troubleshoot Bluetooth detection and connectivity problems in Windows XP Service Pack 2