It is possible that the "Default" Audio device in Sound Panel was changed from AMD to another "Default" Audio device.
Go to Sound Panel and make sure that the AMD Audio device is at "Default"
If it is, then run MS Audio troubleshooter in Control Panel or Windows Settings in case Windows Audio services in not running.
Need to clarify a little bit more.
Are you trying to use AMD Relive to record or some other program to record and it has no audio or is the audio completely off in Windows?
Please post your computer setup : https://community.amd.com/thread/196209
Plus AMD Radeon driver version and Windows version and GPU, Motherboard, CPU/APU Make & Model.