Different PDF versions of Adobe Acrobat have different ways to copy text. In the newest version (8.1.1) from Edit menu, choose "Select all". Then again from Edit menu, choose "Copy". Now you can paste the entire PDF file into a word processing program. Download the most recent version for free. For older versions, please follow these instructions:
In Adobe Acrobat Reader, version 4 or higher, first click the "T" with the small box next to it, NOT the "T" in the small box located in the toolbar next to the magnifying glass (zoom). Highlight the section of the PDF file you wish to copy. Go to "edit" in the dropdown menu and choose "copy". Then paste it into a word processing program's new document as usual.
If these instructions are not useful, please check with your PDF manual, seek Adobe's tech support or contact your own personal tech support.