Solved: MS update killed sound

Twice now a Windows 8 automatic update has killed my sound. The first time a repair shop charged me $80 to "reset the drivers". I can fix the problem now by reinstalling the latest backup image, but now I'm back to an earlier time and ready for the update to be installed again. And there goes the sound again. All my Sound devices say "This device is working properly." If I try to "update driver" it says "your software is up to date". What are these "drivers" I paid to have reset? Why can't I have these available on a disk and "reset" them myself? Why is Microsoft doing this to me? I'm not going to run without updating the machine. Thank you for any suggestions.

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 8 Pro, 64 bit
Processor: Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, Intel64 Family 6 Model 58 Stepping 9
Processor Count: 8
RAM: 16333 Mb
Graphics Card: NVIDIA GeForce GT 610, 2047 Mb
Hard Drives: C: Total - 228833 MB, Free - 123641 MB; F: Total - 953866 MB, Free - 406567 MB; G: Total - 953866 MB, Free - 430465 MB;
Motherboard: Intel Corporation, DB75EN
Antivirus: Windows Defender, Disabled

Windows Defender is not disabled. It says "Real time protection ON, your PC is being monitored and protected" and "definitions: up to date".