I sent the following note to Sweetwater and the tech confirmed he can replicate this. 
 
 
***Start of Note***
•  Rebooted all hardware and PC
•  Opened project corrupted by EZ Drummer 2 (project in which there is no audio output)
•  After hardware reboot, the project DID output audio; however, it still had the following problems:
     - If I opened the EZ Drummer 2 GUI (by clicking on it in the synth rack), I would again lose all audio
     - After another hardware reboot, the audio would come back, but I would not be able to freeze instruments: some would freeze OK and some would seem to freeze but would have no audio
     - If the project is not outputting audio and I close Sonar and open EZ Drummer 2 in standalone, I can see that it has no audio device and there are no devices in the drop-down

This is a problem because it is important to freeze instruments for mixing because: 1-you need a high ASIO buffer to avoid clicks and drop-outs but 2-you need a low audio buffer to avoid latency in the synths.  The normal solution is to freeze all the synths and then select a high ASIO buffer.   It is also a problem that I cannot open EZ Drummer anymore to make edits.
 
***End of Note***
 
Sweetwater's advice:
1.  From Windows Programs and Features, uninstall EZ Drummer 2
2.  From Windows Programs and Features, ninstall EZ Drummer 64-bit
3.  From Windows Programs and Features, ninstall EZ Drummer
4.  Reinstall EZ Drummer from the Toontrack website; HOWEVER, THE SITE IS DOWN RIGHT NOW.