Red X on Volume Icon and Volume Mixer has disappeared

Somehow in the past few weeks, my speakers are working find but no sound. I
have tried uninstalling and re-installing the sound drivers, but still
nothing. I have a feeling that since the Volume Mixer does not display, that
this might be why I'm not getting any sound. I know I might be grabbing at
straw's here but I'm getting frustrated.



Information:

Gateway Computer

Windows Vista (32-bit)

Sound Card: SigmalTel High Definition Audio CODEC



Is there a way to get the volume mixer back?



I tried a few options from other threads but was unsuccessful.



When I go to the Control Panel > Administrative Tools > Services and try to
start the Windows Audio, I get the following error message: Error: 1068 The
dependency service or group failed to start.



Any help here would be greatly appreciated. I haven't had any issues with
Vista until now, and really not sure what to try next.