Strange to say I just the other day paired a new mobile to my laptop (Vista) using an old Cable and Wireless dongle... and it worked.
As always can't remember exact steps but I just let Vista install the dongle and turned bluetooth on the phone on. Clicked the bluetooth system tray icon to find devices and phone was there. Had to enter a pass key into phone that appeared on the screen when picking the phone as item to connect to? (I think it was that way round) to pair the device and not to always ask for permission to connect.
Do you have to make your phone discoverable ?