No sound, please help SOLVED!!

Until today X1a has been working fine for me.

Today however when I play a song, no sound.  None of the tracks or busses show any sound.  In addition the playback won't stop when I hit the space bar or the "Stop" button on the transport.

I have to use Task Manager/End Task to stop Sonar.

The totally bizarre thing is that I was having the exact same problem when I was using Sonar 6.2.1 on a different computer.

I had this computer built for my studio specifically. 

What might be wrong?  Please help, I am at a  loss.

Tom

edit: I found it.  Sonar had dropped the ASIO Playback Timing Master.  Once I reinstalled that, everything came back to life.