How do I select USB out on my computer?

I'm interested in using an external USB DAC but I don't understand how you bypass the internal soundcard in the computer. Can someone please explain the hookup for me?
My laptop recognized my external DAC without so much as a driver. I dont know if the analog output is still active or not--nor do I care. The USB dac works like a charm and the sound quality is pretty good although not up to a good non-PC digital source.

To answer your question, the OS should recognize the new hardware automatically.
Open the control panel, open "audio and sound devices" select audio option.

If you have an usb audio device hooked up select that option from the drop down tab as your audio output device of choice.

You can also right click on the "volume icon" in the lower-right "adjust audio properties"

there are lot's of good, recent posts on this topic. one discovery i have made is that simply selecting the USB device as your audio source (as described by sogood51) may not be enough to produce optimal results. if you are a pc user, you will also need to use a driver other than Windows KMix.

you might search for related threads that discuss asio drivers, such as asio4all and usb-asio. they discuss the pro's, con's and installation/setup of these drivers.

of course, if you are a Mac user, you're good to go.