Presonus AudioBox issue

I'm using Presonus AudioBox and have been recording just fine for months... I did do some rewiring of my sound system the other day, but just speakers and such, nothing to do with AudioBox that I can tell, but suddenly I don't have the option to assign outputs to AudioBox for headphone listening. It is recognizing the box because I can play my keyboard through it and hear that in the headphones, and I can select AudioBox for Inputs, but I can't hear my tracks through the headphones because AudioBox doesn't show up as an output option... I've rebooted and replugged everything (I'm running Windows 7 64-bit). Any thoughts?