For some reason I have lost audio control of the in game "settings". The sliders do nothing. Verified audio drivers and Steam cache. This is a Lonovo computer which is a world unto itself. Everything worked for the first 15 hours but upon restart I had lost control. No hint of problems in Device Manager. Any advice will be appreciated.

Theres a directx folder within your "steamapps/fallout4" and you should be able to run a directx re-installation.

Give it a try...