Help! Suddenly 'cannot find audio playback device'

Hello,
 
I have been using Sonar for many years with no problems.  I am on Sonar x1 Producer
 
Last weekend, I was working in a project and noticed the metronome was not on (it's always on).
 
I went into the Preferences menu and turned it back on.  Immediately, I received the 'cannot find audio playback device' message and it would no longer play/record.
 
I was using WDM.  So I tried changing to ASIO.  This change permitted playback and recording but with much clicks and pops.
 
I downloaded and installed the latest drivers for my interface.
 
I was only on x1b, so I downloaded c and d and installed them.
 
Now, playback in ASIO produces only the horrible digital stutter.  In WDM, I get the error message above.  Oddly, in WDM, when I run the wave profiler, it sees the FF but when I open a project, it gives the 'silent buses detected' message and it will not play or record.
 
I have unplugged, rebooted etc - nothing changed
 
My computer is i7 920 using XP sp3
My interface is RME Fireface 800
I have used both pieces and sonar extensively for at least a year
 
I emailed cakewalk support last Sunday but have received no reply.
 
I'm not sure what to do, but I need my Sonar back!!!!

In WDM, I get the error message above.  Oddly, in WDM, when I run the wave profiler, it sees the FF but when I open a project, it gives the 'silent buses detected' message and it will not play or record.

It could be that the drivers are presented as different names when using WDM. In that case check the driver dialogue as suggested above but also check the actual project routing. I frequently get silence opening some of my older projects that haven't been openend in several versions. The simple solution is my master buss defaults (on older projects) to outputs 1/2 on my ZED which aren't normally routed to its L/R buss, rather than the main outs.

Look at your master buss output and make sure that is set to your soundcard outs. Then look at tracks and make sure that they have their output set to either your master buss or a buss that ultimately ends up at your master buss.