Hi,
I'm not sure I understand your problem?
Can't you just Right-click on the drive you want the folder on in Windows Explorer "C:\" and select "New" "Folder" Create a folder and Copy all your subfolders back into it? Name it anything you want and make the Icon whatever you want.
Leave the subfolders on D:\ as a precaution until you want to delete them.
If you want it to show in Quick Access you can pin it there too.
Mike