It might be that when you installed XP again you have not installed the bluetooth drivers. Do you have a seperate partition on your computer with a folder that has the programs in it that were on the main drive beforew you re did XP.
On mine I have a folder in my "D" drive, its not my restore folder but just one where the programs are when I bought the computer three years ago.
I just looked in it to find what I wanted then installed from there.
Sorry I cannot be anymore help.