How to delete hard drive copy put in folder

My wife can hardly turn a computer on. The desktop fills up with what ever files she has clicked on in her email app. So, I decided to put all her desktop clutter into a folder on the desktop, named “Desktop Folder”.

I did a "select all”, unselected several desktop folders, and drug the contents to the Desktop Folder. Then I realized that the internal hard drive folder was out of place on the desktop and I had drug it into the Desktop Folder also.

So far, nothing I have tried will delete the hard drive image from the folder.

Any suggestions?

The computer is a 2005 something Mini. (not sure which OS).