First one is a fix for XP "lost system sounds". This is where XP will play sounds & video quite happily through Winamp or Media Player, but the system sounds are broke. Download and run these registry tweaks and it all comes back.

Go here and download 'pack.zip' which you will find amongst the thread.  http://forum.videohelp.com/viewtopic.php?t=306701

When downloaded, just open the .zip file and double click on the contents one after the other (3 files)

I was impressed with this, it took me ages to find the fix, but its so simple. Don't try Codec packs, they make more mess than they sort out.