I am embarrassed. 

I want to How to delete Windows 10 'orphan' system files.

Prelude:
Earlier I did an experiment to see what happens when you install Windows 10 64 bit on a partition that also has huge amount of photos in folders. I worked and  I decided to abandon the  Windows install. It is on a 500 GB hard drive.The partition is about 80 GB. So it would be nice to RECOVER the drive space.

Today:
This is not a critical issue. I have the option of just doing a quick format and destgroy the whole partition. But I would rather not go that far. But I just might.

Here is what happened. In an experiment I install Windows 10 64 bit onto a partition that has other files not related to the OS. Later I abandon this Windows installation in favor of using a smaller partition for the 64 bit Windows OS.

This results is some very large 'orphan' files on that partition. I would like to recover the space. Over 3 GB of system  files PERSIST because they belong the OS that I am no logger using. I don't know how to remove these files.
Move on BOOT did not work. The utility takeown can not force ownership. I am stumped. So now I am ready to format the partition and also destroy the other files that I would like to keep. (I have a backup.)

Also, I EVEN tried using Ubuntu demo mode to take control. Ubuntu did delete the folders, but put stuff into a special Linux version of a recycle bin.  So the files still take up drive space.  I don't know how to tell Ubuntu to not keep stuff in a recycle thing. Forget Ubuntu. Tell me how to do it in Windows.
 
Is this the right way to do it?Is there a better way to do this kind of experiment?
Just asking. I am curious.   

This is a triple boot stem with Windows XP, Windows 10 and windows 10 64 bit.  The system works fine. I would like to  recover  some drive space.

Thanks for any insight. 
Can you not extend the larger volume over the partition? Also,I wonder if whether or not diskpart would see that 80GB partition.