> Well, if the right soundcard was not selected, then there would be no
sound
> at all, right? (or wrong?)
You're probably right, but it never hurts to eliminate all possible causes,
and it's quickly accomplished anyway.
But as it seems your problem is solved one can only congratulate you.

Today's soundcards only feature line-level outputs that aren't meant to
drive speakers. You might be able to plug in a set of headphones though...
Opening the manual would probably have confirmed this...
Anyway, good luck with picking your new speakers man. There are many good
choices out there, but you should choose a price range first. I myself use
the Logitech Z680, and I believe there isn't a finer setup available
anywhere in its price range, hehe. Of course, these are overkill for most
people, but the bass on these is extrordinary, and that's what I like.