With the USB3 having normal Windows drivers, a Windows volume control is assigned to it, and sometimes the volume gets set to 10% or 0% or muted. Here's how you check. Go to your Windows control panel, Sounds & Audio devices (or Multimedia in Win98), Audio, set the preferred audio device to be USB Audio Interface, and click the Volume button. This will launch the volume control where you can check the output volume- it should be up all the way to achieve must compatible performance.

If this does not fix it, close this window and any applications currently using the sound card, and flip the sample rate switch on the USB3 to 48k, let it sit for 5-10 seconds, and flip it back to 44.1k (or vice versa if you are intending on using 48k).