Thanks! Hmmm, did that (easy). But, no change (tried all 3 options). I'm pretty sure it has to do with using "stereo mix" for audio input (windows SOUND control panel-which is only choice if no "line in" is used). It really does mix everything, and outputs it so. I rechecked my old strategy of using "line input" with a Roland XV-3080 synth module hooked up. Then, it IS separate, in that laying a new track only uses the new "played in music" to capture, ignoring prior tracks. If that is so, then unless there is some other option (not sure how buses work in this software), it may mean that I cannot use any of the fantastic orchestra sounds from ARIA in Cakewalk, as I can't "line in" that, ARIA sounds are computer produced and only found on "Stereo Mix!"
The only other idea I wondered about was to go strictly MIDI. But, ARIA seizes the MIDI input (USB interface) for playing its sounds out with keyboard, and CakeWalk then can't access MIDI input.