sound quit working

I had to have a new motherboard and CPU installed and several problems
resulted.

I finally got printing back, but I still have problems with sound.

It is INTERMITTENT, so I am stumped.

Sometimes, a few hours after booting, I suddenly have my sound back. Sound
is gone again after next boot.

I'm clueless where to start on this. Still the same sound card I've had for
quite a few years in several different computers.

Jon