No Sound

Sound worked with Windows, does not work with Linux Ubuntu, accept once with an up-date down load from you. The sound worked until I shut the machine off. Upon starting the machine up the next day, no sound, and no sound the past two months since installation. I've plated with System/Preferences/Sound but I can't make sense of those settings.
Thanks for your help on this.
Mike
ProblemType: Bug
Architecture: i386
Date: Sat Jul 21 17:34:34 2007
DistroRelease: Ubuntu 7.04
ExecutablePath: /usr/bin/gnome-panel
Package: gnome-panel 1:2.18.1-0ubuntu3.1
PackageArchitecture: i386
ProcCmdline: gnome-panel --sm-client-id default1
ProcCwd: /home/mike
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-panel
Uname: Linux c-71-232-240-212Mike 2.6.20-16-generic #2 SMP Thu Jun 7 20:19:32 UTC 2007 i686 GNU/Linux

#We couldnt find a suitable wget, so tell the user to upload manually.
else
 if [[ -z $DIALOG ]]
 then
  echo ""
  echo "Could not automatically upload output to http://www.pastebin.ca"
  echo "Possible reasons are:"
  echo " 1. Couldnt find 'wget' in your PATH"
  echo " 2. Your version of wget is less than 1.8.2"
  echo ""
  echo "Please manually upload $FILE to http://www.pastebin.ca/upload.php and submit your post."
  echo ""
 fi
 if [[ -n $DIALOG ]]
 then
  dialog --backtitle "$BGTITLE" --msgbox "Could not automatically upload output to http://www.pastebin.ca.\nPossible reasons are:\n\n 1. Couldn't find 'wget' in your PATH\n 2. Your version of wget is less than 1.8.2\n\nPlease manually upload $FILE to http://www.pastebin.ca/upload.php and submit your post." 25 100
 fi
fi
#Clean up the temp files
if [ -z $KEEP_FILES ]
then
 cleanup
fi