I was testing overclocking settings earlier, and had a few restarts/crashes. Later, when things appeared to stabilize, I found out that there was absolutely no audio at all. SPDIF apparently works (indicated by Windows. I have no SPDIF devices to actually test). Nothing happens when I plug in my 3.5mm earphones or microphone into the front or the back. Playback Devices will always say "Unplugged" under the "Headphone" and "Speaker" entry.
The system is Windows 10 Pro 64 bit with Realtek HD Audio.
I've tried reinstalling the drivers from Asus' (M5A99FX Pro R2.0), Realtek's site, reinstalled them with Windows 7 compatibility mode enabled, uninstalled them from Device Manager, "updating" to HD Audio in Device Manager, cleaned out old driver installs with Driver Sweeper, and even resetting my BIOS settings. Audio doesn't appear to work in my Arch install either, but I don't remember setting up audio on it. I booted Ubuntu 14.04's Live USB, which I assume has audio configured, but I heard nothing through my earphones. I also tried restarting the audio services, and updating the board to the firmware. Nothing's working
Earphones do work when plugged into my phone