Why doesn't the Play button Play in Premiere CS6?
Okay, this worked for me:


Re-Plug-in ALL your External Sound-Hardware.
Open your Sound Menu from Windows and set your Microphone to your current one. (For me it was the external Soundcard)
Now Open up Premiere Pro and set everything on your Preferences as previously stated.
Save your Current Sequenz/Project. Close premiere.
Reboot your PC.
Check your Sound Options in Windows, if everything is set right.
Open Premiere and check again, if your Prefences are still in (everything should be in order)
Now hit play.
If the Re-plugin doesnt work, use different USB slots :)


Hope I could help you.