[CentOS] Sound failure in CentOS 6.8

Sound stopped working on my CentOS 6.8 system several months ago. I've tried 
everything I can to find out what's wrong. It is not the hardware; if I boot 
into a live dvd of 6.8 (or any other OS), the sound works perfectly. So 
something must have changed in my configuration.

I've compared files on my system and another CentOS 6.8 system with working 
sound and I haven't found any differences relating to sound configuration.

I've scoured the web for help, and found a few sites where people reported the 
same problem, but none of their "solutions" work. Many refer to sndconfig and 
system-config-soundcard which don't exit in 6.8.

I've spent countless hours looking through alsa (and other) documentation for 
any hints that might help. Nothing.

If I crank up the volume on the speakers, and set kmixer to max, I hear a low 
level of white noise coming from the speakers. This noise does not occur when 
I first boot up, but kicks in somewhere during the boot process, I'm guessing 
when the system is attempting to initialize the sound card.

The only substantial info I have about the failure is the output from 
KInfoCenter -> Sound:

--------------
Sound Driver:3.8.1a-980706 (ALSA v1.0.24 emulation code)
Kernel: Linux 2.6.32-642.3.1.el6.x86_64 #1 SMP Tue Jul 12 18:30:56 UTC 2016 
x86_64

Config options: 0

Installed drivers:
Type 10: ALSA emulation

Card config:
HDA Intel PCH at 0xfbff8000 irq 33
HDA NVidia at 0xfaffc000 irq 17

Audio devices: NOT ENABLED IN CONFIG

Synth devices: NOT ENABLED IN CONFIG

Midi devices: NOT ENABLED IN CONFIG

Timers:
31:system timer

Mixers: NOT ENABLED IN CONFIG
---------------

I have no idea what "CONFIG" it's referring to.

A gigantic "thank you" to anyone who can help resolve this problem.

Jeff