My subwoofer won't work!

Hi there! I'm new around here and i thought using this forum will help fix my problem. The problem is about my sub that it won't work. I recently installed win xp professional sp2 and installed the drivers for my sound card Creative SB X-Fi XtremeGamer. I have to mention that is a 5.1 surround. The drivers are up to date (version 2. 9. 2). The plugs are connected to their correct jacks (green, black and orange) as it shows in the manual. So, after installing the drivers and all my programs, music, games and other stuff i wanted to listen some music but my sub didn't work. I tried to play music in different programs but the same. On internet if i wanted to play music or if i wanted to see a movie the problem didn't disappear. I tried to fix it from the volume panel of my creative sound card program but nothing. I even reinstalled the drivers but no change.
Now the big thing is that before installing win xp prof sp2 i had the same OS on my computer but then my sub worked perfectly. The OS is the same that i reinstalled few days ago. Is from the same cd. I reinstalled it because of several errors, but now i can't think of something how to make my sub work. I went in the volume panel of creative sound card program and test the speakers, in THX setup console too. I tested the speakers and they work perfectly all - even the woofer. It has that specific sound...i make the speakers assignment and all work as it should be. But when i try to play some music or watch movies or play games the sub doesn't work at all. Al the speakers work but the sub nothing.
Another thing that i want to add is that the sub made the same trouble last time i installed the OS but then suddenly it worked, or i pressed some button that i don't know now.
Can someone please help me? This thing is getting on my nerves...:upset:

Thanks and have a good day!