5.1 System, Everythings works, exept music

[nofearskill]

Iv bought a Logitech X-530 5.1 Sound System a month ago and used a 5.1 C-Media Sound Card witch is very old, 2002 or something. Everything worked but the sound card was way to old and i cold hear weird noises come from my speakers so i decided to remove it since my motherboard advertises that it has 8-Channel (7.1) HD Audio Subsystem. (it has only 3 audio outputs).
Plugged all the cables in, inserted my Star Wars DVD... everything works perfect. Then, i went on youtube and tried to listen to some music and i noticed it only works in stereo. I know Flash can't handle 5.1 but whit the old soundcard all the speakers were working, now only the left and right speaker work.

I also messed whit the driver and the 5.1 works flawlessly, If i press the Left Speaker, the left speaker works, if i press the right rear speaker, the right rear speaker works, if i press the subwoofer, the subwoofer works etc...
But on youtube, or other mp3 files, it only works in stereo. how can i fix this? (Also tried the speaker fill... it just sounds weird.

Motherboard: MSI G31TM-P21
Sound Driver: Realtek HD Audio Manager

Sorry if i did not post in the right section.

 

[ssddx]

the speaker system is perfectly fine. music and web sounds are typically stereo or mono and will not play over the rear speakers unless you make that chance in your audio properties. keep in mind that when you do this it can disable true 5.1 until you change it back depending on your particular drivers/software.