Windows 7 - ?Headphones Realtek Surround Problem?

Hi, yesterday, my father gave me one Headphone, with surround effect, when i was using it on my computer, i noticed in the realtek audio manager, that i could put the surround 5.1 effect, it was working all fine, but today, when i used the headphone again, the surround effect was on, but i dont know what happened, it was like it was off, what the hell?? When i went to the control panel and selected "Hardware and Sound" (yesterday) like this: http://img862.imageshack.us/i/semttulorxk.png/ those selected speakers were working just fine, but today, for some reason, it works only on stereo! I installed and unistalled the realtek HD audio and it worked nothing! Can somebody help me here? How its possible from one day to other without touching in anything, the surround just... just DISAPEARED!?