I did notice that you have a folder entitled *My Library* under your *My Documents* folder which contains a runtime folder.  To check if this folder exists in your Library, navigate to *Show Library* at the top of the Library window and click on the arrow to open the menu.  Select all.  This action will reveal all the folders containing runtimes on your hard drive.  The image shows some of my own external, individualized runtimes I have created. 

If you do not see your own folder then you need to add it to your Library.  At the top, right (circled in red) is the add runtime button.  Clicking this button will open a browser where you navigate through your hard drive to your new runtime.