You could try it but I doubt it's anything to do with media player. Please see my previous post and what others have to say. It may have been working before but that probably won't actually help with resolving the issue. Cheers..

OK, Doktor, thanks.  Whenever something just stops working when no changes have been made, it makes me wonder.  I know I didn't change drivers.  I do know that Windows makes updates whenever it feels like it. So, I'm jujst trying to get a handle on this.  As always, the help and advice are much appreciated.

Yup but just because you didn't change the drivers does not mean you can rule out the drivers. Thanks...

And I'll repeat, This issue is common and it is DIFFERENT on each system. 
It really seems to be up to how the ASIO drivers "share" if you set that option. 
I use my interface exclusivly because I do not ever playback anything but my studio music on my DAW. 
If your DAW is not exclusivly a DAW but used for "do all" computer stuff like surfing etc then the on board option might be the best.
 Me I need to hear all music playback though my studio monitors. 
I disable windows sounds and they seem to stay disabled unless I change a theme. 
 

Total stretch, but try creating a new user account and see if the new account has the same problem. If it does not, you might be bumping your head on drm issues.

I always have windows system sounds turned off. But I don't want to have to change my interface from ASIO to listen back on WMP to some audio for comparison sake.

As WMP is what some people will be listening to music on I want to have that available on my DAW to see how a mix might sound through WMP on computer soeakers.

sharing drivers in Sonar is in a way mis labeled as the driver will always be available to any program that can address it. The only difference is that when sharing in Sonar is checked then only the program with Windows focus can access the driver. When unchecked all programs that can address the driver will be able to do so simultaneously.

Maybe I am missing something, but here is my question.  If my drivers are messed up, why are they fine until I use Windows Media Player, and then why does a reboot fix it?
 
Under Sounds in Control Panel, I disabled Speakes and Headphones and left VS-700 as the default device.  That did not change the issue.

Because with some ASIO drivers WMP or other Windows music apps will change your mode from ASIO to WDM or ?  and / or if your projects were 48 it will turn them to 44.1. But as I said this really depends on which interface your using. This never happens to me anymore. 
Rebooting puts Sonar back to it's defaults. 
 
So I think for those of us who have no problem we only need an ASIO audio interface for all audio.
But for those who have your issue then you should probably use your on board audio for Windows Apps. Or like Bob try the HDMI. 

Windows can't use ASIO drivers but a device can be access by two different drivers as long as different inputs and outputs are selected for each
Example ASIO driver IO 1 and 2
MME driver IO 3 and 4

Make sure that in Sonar that the input and output timing device is not a channel you want to use with the other driver otherwise you'll create a mess.

konradh
Maybe I am missing something, but here is my question.  If my drivers are messed up, why are they fine until I use Windows Media Player, and then why does a reboot fix it?
 
Under Sounds in Control Panel, I disabled Speakes and Headphones and left VS-700 as the default device.  That did not change the issue.

See my very first post. It's all about the driver and it's environment.