Logitech X-530 5.1 - Subwoofer is barely audible

I got these back in Spring:
http://www.bestbuy.com/site/olspage.jsp?skuId=6675065&type=product&productCategoryId=cat01055&id=1083710678341

They worked phenomenally, and the subwoofer was so powerful, I could barely turn the volume on it up, before it really got loud. Then, my HD started failing, and I had to buy a new one. In that time, I used the speakers with my XBox, and they still operated just fine. But when I finally got my new HD back in April, I noticed that my subwoofer was nowhere near as powerful as it used to be. Now I have to use WOW Effects in WMP just to get results.

Windows XP Service Pack 2 Intel Premium 4 CPU 2.93 GHz 503 MB Ram

Realtek HD Audio

The other speakers seem to work fine, but I have to turn the volume on the subwoofer all the way up, and it's still kinda low.

I updated my audio card drivers as well. According to my volume settings, my
subwoofer is at max volume.

I'd really like to enjoy movies such as Terminator 2 in full 5.1 glory, how would I go about fixing this problem?

 

I also have these speakers and love 'em!

If you go into your mixer settings for the C-Media mixer and choose advance settings, go to the "sound effect" tab and choose "enable virtual 5.1 settings" - does this help?

Also, are you using Xear 3D?

 

C-Media? I have Realtek, I can't find those settings. Never heard of Xear 3D.