In my last post on Bluetooth I tentatively concluded the Intel software & drivers for both WiFi and Bluetooth are now properly installed with entries in Device Mgr as per your advice. But during my first attempt to actually use Bluetooth, during a partially successful attempt to pair and use a Plantronics BT Headset, something happened (maybe something I did wrong) that caused the Bluetooth entries to be removed from Device Manager (No 'Bluetooth Radios' in root, and no BT in 'Network Adapters', and there is now no Bluetooth icon in the system tray. I also notice in Device Mgr, under the 'USB controllers' entry, the earlier issue of 'Unknown Device' has re-appreared - where in 'Properties' I see it uses Port 007, which I eventually discovered is used by the 7260 card. WiFi still works.
In the Control Panel>Uninstall, I see Intel PROSet/Wireless Software for BT 17.0.1405.0466 67.5MB listed.
I re-installed from BT_17.0.1405.02_s64.exe dated 26/7/14 but nothing appears to have changed.
Can you advise what I need to do to get Bluetooth to re-appear ?
I followed your advice and ran the Intel Graphics driver (GFX_Win7_Win8_Win8.1_64_10.18.10.3345) again, but no joy. Currently, there is a red x mark on the Volume icon in the System Tray - unless I plug in external audio to the 3.5mm socket. (ext audio works) Today I repeated the install, the only difference this time, is there is no red x on the Volume icon. (In Volume>'Playback devices', the HDMI Monitor does not appear, only Speakers-RealtekHD Audio, Default device)
Can you think of what else to try ?