There are certainly some things that can be checked out. Here are a few questions that might help start the process:

1. What sources do you have connected, and how are they connected? (For example, if it's just the DVD player, are you using coaxial digital, optical digital, multichannel analog, or some combination of those?)
2. What amp are you using? Can you confirm that it is on?
3. Do the internal test tones give you anything?
4. Aside from the lack of sound, does the unit appear to be functioning? Front panel display on, responding to commands from the remote, video output working, on-screen menu working?