Re-enable sound card driver

Hi-
Just starting my first project using Sonar LE with a Tascam US-144 interface. I set up Sonar for input and output to the device. When I went into the 'drivers' tab under Audio options, I unchecked my computer's sound card to disable it, figuring that would help avlid conflicts. Problem is, now I'm sitting here without the device and would like to listen to what I recorded though my computer's speakers, but now that driver doesn't show at all as one of the options. How do I get it back?