I recently used melodyne but couldn't find it under RegionFX. Found knowledge base  about VST3. Uninstalled and reinstalled making sure to check VST3 option and VST2 ,since I know 2 works. Nothing. I let it install uninterupted. Help!

This sounds familiar. I don't recall the bundled Melodyne Essentials providing a VST2 option. At any rate VST3 is required for ARA (Region FX). Solutions in the past have been, apply X3e, run a VST reset and rescan (instructions here http://www.cakewalk.com/Support/Knowledge-Base/2007013315/SONAR-X3-Full-VST-Rescan-Recommended-for-Upgraders ) and updating MS Redistributable C++ libs. If the first two don't work, I could contact both CW and Celemony tech support.

Found it. It was in a VST3 folder in program files>common files>VST3. Weird, cuz I did a search for VST3 and just got some generic documentation. Melodyne also never prompted me for a location to confirm or change for VST3 install. (it did for 32bit and 64bit VST2 though, their default was in a Celemony subdirectory. I installed them both,in case I was stuck as far as VST3/ARA was concerned) I just added the VST3 location for Sonar to scan and voila! Works great now!

The VST3 path is part of the VST3 spec. The path is not user selectable like VST2 so VST3 compliant installers don't prompt for a path.  I thought the VST3 path was part of the default SONAR scan path configuration. Glad it is working for you now.