Hi miz786,
Do you have a 32-bit or 64-bit version of Windows 7? I hope it's 64-bit, as there are not any Intel graphics drivers available for Windows7 32-bit, unfortunately. If you are using 64-bit, then perhaps there is some sort of mismatch or corruption in the audio driver. You can try resolving that as follows:
1. Uninstall the graphics and audio drivers, using the instructions at Graphics — Uninstalling the Intel® Graphics Driver and Intel Display/HDMI Audio Driver
2. Restart the computer.
3. Install the latest graphics driver for the Intel NUC (this will ensure the corresponding audio driver is installed too).
Regards,
Lois H.
Intel