OMG! WHAT WAS THAT?!
Holy Moley! I just spent the better part of an hour trying to wrestle Yosemite back into running iTunes, which it just suddenly decide to stop doing (probably because, like a dummy, I've had my system set up so Apple can sneak in and "update" — aka: "Trash"— my system when I'm not looking.) I'm a twenty-year Mac veteran and tried everything to uninstall (pretty much impossible, since OSX "needs" iTunes), overwrite with an earlier version (says it installed but can't be found), trashed all pref files... tried everything... then found Goober5's solution and BAM!... worked right away.
Thanks Goober5! You are my brand new best friend!