There's something wrong with my computer volume?

Normally my overall computer volume is set to a comfortable 25%, but after listening to a song with a WMA extension file, it seems as though my volume has become softened. I now have to increase my volume to about 50%. Several other programs need their self-volume set to maximum, and I'm receiving static noises from other programs, as if they're "losing transmission" half way through the "message." I'm pretty sure it's not my sound card since I bought a new one fairly recently, and this only occurred after listening to said WMA file. What caused this and how can I fix it?