Losing folders in My Documents

I have owned Dell computer's for 10 years now.  I put all of my documents in the My Documents folder.  Recently I have lost folders in the My Documents folder.  Fortunately I have managed to back up the My Documents folder.  However I have lost some folders and files.  For me this is a very serious matter.  I have even lost files and folders within an existing folder. My procedure for backing up the My Documents files and folders: was to create a folder called ‘copy of My Documents’. I then open up the My Documents folder, select all the folders and files, copy them, and paste them into the ‘copy of My Documents’ folder. This method has worked well for me. I haven't a clue about why my folders and files are being lost.  The lost folders and files have been sporadic within the My Documents folder. Can you help me?

James P. Irwin

Note: I have never known how to back up the My Documents folder directly.