@puppybyte!:This is just a
theory as most of the machines I work with all have sound cards built in, but none of them are wired to make noise
It's my guess that pavucontrol is likely leaving a configuration file somewhere when it's first started and it's being lost when you reboot.
If I were to venture a guess, this file may be stored in /home/tc.
IF your system isn't set to ignore backups (norestore) then here's something to try:
1. Start the mixer (pavucontrol) so it creates its configuration
2. Open a Terminal window and type in
filetool.sh -b and tell me if it responds with "OK"
If it does, reboot and see if your sound is working without intervention