For PowerPoint, Word and Excel file there is a native protection.
All documents, that are printable, like Word or Visio can be protected by creating a PDF file. See details PDF protection. This is the recommended and most flexible option. Most applications allow to save as a PDF file or print as a PDF.
If you do not have any PDF tool, download PDF creator: http://www.pdfforge.org/products/pdfcreator/
A different way to protect office documents, is to convert it to flash using a printer driver. It is called Print2Flash and can be downloaded and bought at http://print2flash.com. It has not all the options the PDF Viewer offers but it requires no installation with administration rights on the end user PC.
Download a sample - the All-In-One Protector Tutorial with over 200 pages and links inside the PDF document - converted with Flashpaper - Click here to download and unzip the file to a folder. Start mp-flashpaper.exe.
See also
Word with Hyperlink