It would have given an error then, I think, not played silent, anyway.
Are you sure you don't have it muted? Under the speaker icon from within MC, or the Windows sound control?
Assuming not, run through the
Audio Setup section of the Wiki again. It is possible it is trying to play to the wrong sound device (though if you imported settings when you did the restore suggested above, then it should have copied your settings entirely).
If that still doesn't solve it, please describe in detail what options you have set (all of the stuff talked about in that wiki article).