Carlos, Glad to hear you figured out Itunes. On Windows media player, the EQ is listed under View-Enhancements, then choose "Show enhancements" . Now you'll see the enhancements on the bottom of the screen, and to choose between them use the < > arrows in blue. There are 8 choices. Go through each one just to check the EQ, SRS WOW effects, and "Crossfading and Auto Leveling" are off. Also make sure the play speed is set to normal, it's probably set that way by default, but you never know.

BTW, as Gonk stated earlier, using the USB connection, the 2150 becomes your sound card. Try connecting some headphones to your sound card or computer while you have the 2150 connected, and you'll find there is no output. You can only have one sound card active at a time. Disconnect the 2150 and it goes back to your sound card. That's the beauty of using the 2150, no matter quality of your sound card on your computer, connect the 2150 and you have high end sound. I get some RF interference from my Sound Blaster card, so using the 2150 instead is very welcome.