These files are copies of documents you are working on, generated automatically by the operating system. Imagine that you are writing a large report. It takes you a week of work, several hours each day. Every time you open your document, Windows creates a temporary copy of it. You are actually editing the copy of the document not the original. When you press 'Save' you update the original with the changes from the temporary document. However when you shut down your computer, the temporary file may still linger on the disk. After a week of editing, you will have several versions of your document in these temporary files, at different stages of completion. Even if you destroy the original using Eraser, the temporary files will remain on your computer.
<img>
[[File:Temporaryfiles4.gif|temporary files]]