"no volume control gstreamer plugins and or devices found"

Last week, i faced a bizarre sound problem on my Ubuntu 7.0.4 and all of a sudden my sound card seems disappeared.There was a red mute icon on volume control and if i click on it, it gives a message "no volume control gstreamer plugins and or devices found" .Obviously, i Googled.First i checked whether my user account got access to audio device and then i checked whether restricted codecs are installed properly.Generally, If your user account doesn't have access to audio device you may face this problem.But everything seemed OK in my case (System>Administration>Users and groups).I feared i had to install whole OS again.Luckily the following guide saved me.I reinstalled my ALSA drivers and rebooted my system.Magically it worked and happy ending.This is the third time, i faced sound problem in ubuntu and last time it was with micro phone and YouTube videos.I discussed 'ubuntu microphone problem' in one of my previous post.Hope this helps people who are in need.