Auzen X-Fi Forte not sounding properly with games/movies (help!)

[annoluce]

Hi guys,
I'm writing here for the 1st time after a period of lurking. I appreciate this community.
I have a problem with my Forte X-Fi, but I fear it can be a problem of Windows because the same problem occurred with Essence ST.
As far as the music playback is concerned, everything is just fine and I get a good quality with foobar/wasapi.
When it comes to games/movies, the sound is very poor.
I tried: Skyrim, BC2, Alien vs Predator, Starcraft2. And Star Wars ep III.
That's what happens:
sound is very very muffled, character voice is muffled as well and highly recessive (the voice acting seems to be sinked beneath other sound effects like wind, weapons, environment sounds etc). Same thing with movies. Sounds like guns and environment is overwhelming with respect actors voices.
In general, I can't get a crisp sound whatsoever.
I listen primarily with headphones, namely Audio-Technica M50. I tried these cans on a friend pc with a Xonar DG and everything sounds beautifully with Skyrim!
Could it be a problem with Windows?
I tried ANY possible combination between soundcard settings and windows settings: stereo, 5.1, 2.1, and any mode (entertainment, audio creation, gaming). No way.
I also tried to separate the card from the video card in the case to give it more room (maybe overheating??). No way.
Next step will be reinstalling the OS. But I don't expect major improvement.
Is there someone who can help with this, having had the same experience?
This card is famous for its gaming skills!!! :-(

Thank you.
Max