You don't really ever want to use 2 sound cards at the same time. You can, but it generally simply leads to problems.....

Pick one.

Most folks use the sound card that's connected to the computer. Internals can be used.... but in my case, I don't use the internal sound card, I use an external card for ALL music related activities. Also be sure to use the proper driver that the manufacturer recommends.

My external is a Focusrite Saffire connected by firewire with ASIO drivers.

ALL inputs from audio sources, including mics and guitars go to this Focusrite interface. It routes the audio into the DAW as needed and into the track I want it to go to. This routing is selected from inside the DAW when I set up the track inputs.

Saffire audio (left, right, and stereo) shows up in my audio input options and I simply select it as the input on a track by track basis.

OUTPUT from the DAW is back to the external sound card (focusrite)by default, where I have my active studio monitors connected. I never need to select my outputs, only the inputs on a track by track basis.

Midi works the same way. Midi into the focusrite, into the DAW as selected in the midi tracks in the DAW..... and audio back out to the focusrite.

hope this helps

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.