I have an Intel NUC PC which I have just upgraded to Windows 10. It is connected to my TV via an HDMI cable. Everything works fine when I start up the PC. When I right-click on the audio icon at the bottom right of the taskbar and then click playback devices, it shows a single entry for HDMI Intel(R) Display Audio and this is working fine. However, if my PC goes into sleep mode which switches off the display and is then "awakened", the audio icon on the taskbar has a red X next to it. Checking the playback devices now shows that there are no playback devices and I have effectively lost all audio. The only way I can get the audio back is to restart Windows. This is not ideal and neither is setting the PC to never go into sleep mode which is the only solution I have found to date. I have tried all the solutions suggested by people with related problems such as running the troubleshooter, updating the drivers, turning the audio services off and then back on again etc. None of these work. It would be much appreciated if someone has encountered this specific problem and has found a solution. Thanks in anticipation.
UPDATE: i think I have solved my problem.
As a rather long shot I figured that if I had not been having this problem with Windows 8.1, maybe I should try the 8.1 drivers. So I googled "Windows 8.1 Intel(R) Display Audio" and came across the Lenovo support site (http://support.lenovo.com/us/en/downloads/ds040008) which had the 8.1 drivers. I downloaded the exe file via the download link provided. double-clicked the exe and the installation proceeded without any hitches and requested a restart of Windows which I did.. I then ran a few apps (mail, Google etc.) to make sure everything was working fine. I then switched off my display (tv), waited awhile and then switched it back on. Voila! My audio was still working. I am cautiously optimistic that it will continue to work and not cause any other problems. I hope this may be of some assistance to others who may be experiencing this problem.