If you had the problem with Bluetooth peripheral device driver installation prompt while using Vista then my following experience could be useful to you.
I wanted to connect Nokia N73 to a Vista based PC. First I activated Bluetooth on the PC and then installed Nokia PC Suite (version 5.8). The device (that is N73) could be located by the PC but there was a persistent prompt about Bluetooth peripheral device driver installation. The system was laptop with built-in Bluetooth and PC Suite was installed so I wondered why should there be an additional driver requirement. I found out that others with more recent versions of PC Suite also experienced this problem.
When driver as prompted could not be installed, I went to Control Panel > Hardware and Sound > Device Manager and deleted anything related to Bluetooth showing unsuccessful driver installation. These unsuccessful installations showed at different location from Bluetooth Radios location inside the Device Manager. After deleting them I explored at this separate entry titled Bluetooth Radios inside which there were two entries, one saying Generic Bluetooth Radio and the other saying Microsoft Bluetooth Enumerator. I disabled Microsoft Bluetooth Enumerator. Now, I uninstalled Nokia PC Suite and restarted the PC (the PC Suite uninstallation wants system restart).
After system restart, I again activated Bluetooth on the PC. Since, I had to install Nokia PC Suite again; I went for the recent version 7. After that there were no issues. This blog post is being typed while N73 is connected and I am able to access Internet at this moment via N73.