When I installed Ubuntu, everything was great. But one day, I heard the login sound but no sound on the desktop session. This happens every time. I have reinstalled sound drivers several times, checked that the speakers are not muted, checked the settings in alsa-mixer, tried all the troubleshooting tips on the net, checked user privileges too but of no help. This is a real problem, please help! I am using Ubuntu 10.04LTS and a alc662 sound card. My computer is detecting the sound card and there are no problems with my speakers.This maybe a bug but I cannot file a report as I don't have enough information.
I have had similar experiences. Audio worked fine and then during my login session it stopped. I found a few interesting facts about this. First I removed the .esd_auth ,pulse-cookie and .pulse directories. Then I rebooted and audio can back. That lasted a while and it happened again. Now I find that simply logging off and on 2 or 3 times resets the audio for a while. Sorry this is not a solution, but might help.
Try to determine what "dot" directories in your home directory are audio related and see if they are culrpit. Easiest way to tell? Create a brand new account and log into it. If audio works then the problem is in your configuration and not the system. Look at the dot files and directories in the new account, one of them (or more) deals with audio and you can replace your directory/files with the ones from the new and working account.