No Audio Device

About a week ago my audio and video disappeared after working flawlessly for
several years on this computer. I am running WinXP and have video in Windows
Media Player, but the audio is silent there, as well as all other programs.
There are no conflicts listed in Device Manager, but Sounds and Audio shows
"No Audio Device" even though the latest drivers are installed and reported
to be working properly.

I noticed that quite a few others here also reported the sudden loss of
audio capability around the same time. There is no way to check my Update
Log showing in Add/Remove Programs, but I did Start/Run to pull up the
notepad and can't figure out what I'm reading. I really need to know what
can be done to recover it ASAP as we rely on Messenger and Internet telephony
to keep in contact with our daughter while away at school. The strange thing
about it is that she has been working on a similar problem for the past month
or more and can no longer receive video, either. 'Tis a mystery and a
frustrating one at that! Hope someone can provide some insight to get us back
on track. TIA-pda