Vista - USB headphones not working

I have a Logitech USB Headset and Windows Vista
When connecting, the sound keeps going through speakers instead of headset.
PC recognizes the headset when connected. I can even control the volume
through the headset control, but sound keeps going through speakers.
These headphones dont have drivers, they use the OS driver.
If I access Control Panel>Sound>Playback the headset is recognized. The only
way to make the PC to send sound to the headphones is if I click Test in the
Playback tab.
I also changed the default playback device to the headphones and no change
at all.
I even accessed Control Panel>Device Manager>Sound and uninstalled the
driver for the headphones. Then I plugged them back to the USB port and
installed properly but still no sound.
Please help if anyone knows the solution
Thanks