When you scan text from a document, the scanner is merely taking a picture of the text and saving it in an image file, such as a TIFF, JPEG or PDF. This means you can't copy, paste or edit it like text in a word processor. When using Windows, however, you can employ Microsoft Office to handle this problem. OneNote, a program packaged with Office, takes images with text and extracts the text, meaning you can save it and edit it like any other text.
Click "Start | All Programs | Microsoft Office | Microsoft OneNote."
Click the "Insert" tab, the "Picture" button, then the "Insert Picture from Files" button.
Select the text from the image, and copy and paste it into a word processor document. The text from the image is machine-readable text you can copy and edit.