lost sound on dapper

I suddenly lost sound, and can´t figure out why...
This is kubuntu 6.06 (dapper).
ATI sound card was detected and configured when I installed a year ago,
and until just yesterday, I was enjoying sound.
Now, I have no sound.
The sound card is still detected, and I have done nothing to alter
related settings.
There are no other processes hogging the sound card.
Kmix is configured to have the volume up.
I get no error messages.
I can stop and restart the sound system in KControl,
but, I can not get even a test sound (nothing happens when I click
the test sound button).
I get no sound from any program, nor even start-up sounds when re-booting.
The speakers are plugged in and on, and I have tried two separate sets
of speakers that work with other devices connected to them.

I´m lost for ideas....

The only difficulty I experienced prior to the issue was while
playing music from a migente.com profile (like myspace, pero en español).
It got all garbled and staticky. The next time I logged on: no sound.

This is on Ubuntu Dapper.
ATI onboard soundcard.

Any and all assistance appreciated as always.