I've had endless issues with this as well. Dell Latitude E7450 with the Intel bluetooth adapter, on Windows 7 Pro x64
Firstly, the Intel drivers don't install properly, the installer gets to a point where it wants to install the connection manager application, after which it fails and exits.
I ended up extracting the MSI and installing the driver manually, which worked.
Then I paired up the QC35, and it detects okay but disconnects and remains disconnected afterwards. I am unable to configure the bluetooth services.
How I solved this was by replacing the MS bluetooth stack with the Toshiba stack for non-Toshiba notebooks (http://support.toshiba.com/drivers)
The headset needs to be turned on when you start up the OS, otherwise you won't have audio. A workaround is to delete the pairing and just re-pair the QC35 with the OS.
I suspect the reason for the issues with the Windows BT stack is that Windows 7's stack implementation isn't version 4 compliant and doesn't advertise the computer name to the QC35 properly, causing the QC35 to drop the connection.
I tried the WIDCOMM stuff but that requires Broadcom/QLogic chips, and I don't believe we should be paying for stuff like BlueKitchen to get something to work that is supposed to just function out the box.
I hope this helps some of you guys out.