no sound at all audio switcher out

Everything worked ok until a few days ago.  Then Win XP scanned my C hard drive, saying it might be corrupted.  Now I get no sounds or audio whatsoever- neither system sounds nor any video audio (of any format.)  When playing a video I get a warning window, something about pins failing to connect with audio switcher out.
    I scanned the faq, and my eyes just glazed over.  
    Any suggestions?  (My speakers work ok -tested on another machine.)
I don't understand much about audio and video, so please keep your answers/suggestions detailed but KISS.
    Thanks very much!!
                  rons5150  (my first post here)
   

1) Re-install your sound driver.
2) Start > Run > execute this command: sfc /scannow
This will detect and replace damaged Windows files.
3) Re-install the codec pack
4) Create a backup of important files. Once a harddrive starts giving problems, it usually get worse.