Unfortunately, no succes yet. The installation of the Intel drivers provided a strange message telling me that I was trying to install an older version. But when I persisted, the three problem drivers were back there after a restart. When I had the software look for the proper drivers on my harddisk however, it found the Broadcom drivers that I had downloaded earlier and started installing.
The three unknown problems have since changed into:
1. Human Interface Devices - Bluetooth Remote Control
2. Sound, video and game controllers - Bluetooth Hands-free Audio
3. Bluetooth Virtual Devices - Bluetooth L2CAP Interface (hidden)
All three use Broadcom drivers and are marked with an exclamation mark : "This device cannot start. (Code 10)"
At least I have some idea now about what these devices are, but I don't understand why device manager "sees" them when there are not there. The Intel versions of these devices are all present and working under "Bluetooth Auxiliary" (hidden).
Any suggestions?