In Bridge go to edit/preferneces/file type associations and select the extension and then you may have to browse to CS6.exe. If a lot of them are fouled up you can try the radio button on bottom to reset all.
Thank you, Curt.
I figured it out an hour or so after my original post, but forgot to revisit and update.
I still don't know how all the extension settings were broken, CS6 was working fine until three days ago!
Anyway, thanks for responding, this seems like a very helpful forum.