In windows 7 operating system choose the playback devices, pick an hdmi device not connected, and go to properties: now change the settings. later, choose the driver tab, update the driver and the high definition audio driver gets detected.. Hdmi sound not working on laptop, running windows 7 and the spdif is missing? he forum missing driver files for win 8.1 setup solution epiphan hdmi2pcie v3 video capture card driver or software. Home