I just got a Nokia with Bluetooth, i got a USB bluetooth adaptor,a Belkin. I have to say a little tricky to setup, and prone to some "funny business" but when it does decide to work its the dogs!!!!
I have XP, the Belkin has XP drivers but are not signed by Microsoft, XP does not seem to recognise Bluetooth, so it said!!!!
That may explain the odd behaviour...
It does seem to have settled down and seems to be OK ..
There are several other makes of USB adaptor out there, so have a look around..
It is worth it ,, have fun
Kitz E Kat