Hey Eddie. It looks like you can call the MS order desk and get a replacement. This site doesn't mention what it costs.
(this page is for MS Publisher but I'm sure it's the same thing for windows)
http://support.microsoft.com/default...b;en-us;302822
"To obtain a replacement disc call the Microsoft Order Desk at (800) 360-7561 and request a replacement for your damaged disc. If you are outside the United States, contact the Microsoft subsidiary for your area. To locate your subsidiary, see the Microsoft World Wide Offices Web page at:
http://www.microsoft.com/worldwide/"