That means you needed to configure (and maybe even install) the proper drivers for your soundcard.
Putting those entries directly into the registry is not a good idea as they might/are different for everybody and it depends on what sound card you have etc.
That this worked for you is somewhat a coincidence. Well, not entirly though, as those drivers you listed are mostly the generic drivers, but still. You now might have other problems hearing sounds or playing stuff with other file formats and/or codecs..
Anyways, as said you should've checked your sound configuration and drivers in your Configuration Panel instead of manually adding (maybe incompatible) associations for drivers...
/ 
