If you are using the same audio interface for programs other than SONAR, make sure the Windows settings for the interface are the same as the settings in SONAR. This might explain access issues with the audio interface.

I think I may have solved the problem but I'm pressed for time and will have to wait until tomorrow to fully test it out.
 
When Sonar loads it does a VST scan and I could well have a dodgy VST instrument or effects that came with advertising that launches when the instrument/effect is loaded.  I had updated my drivers before but when I checked the date of my driver it was dated 2013.  I uninstalled and deleted the driver before the second attempt.  Now I have PC sound while Sonar is open.  Tomorrow I will find out if Sonar itself has sound but with everything behaving as it should do there is no reason why it shouldn't.  Thank you everyone for your assistance.