Dell Latitude Bluetooth Solution after installing XP service pack 3

Problem:

After installing Windows XP service pack 3 my Dell Latitude D810 lost its Bluetooth . I couldn't switch Bluetooth on using Function F2 (The blue light didn't go on). Since I couldn't switch it on I couldn't use any bluetooth devices.

Fix:

I followed XBoxBrians solution from this thread. Basically downloaded the Toshiba Bluetooth stack from here. I installed it (it firstly uninstalls the existing stack). This updated the bluetooth software and drivers and seemed to fix my problem. I can't promise that it will solve yours but I hope it helps!