Hello Bryan1956,
I only deal with Activation or Validation issues, so I have no idea if/how to recover a worn COA sticker/Product Key, but possibly the below Support Docs may be of some assists you.
To Replace Product Key:
See KB811224 "How to identify, locate, and replace a product key" http://support.microsoft.com/kb/811224
or
See KB824433 "Lost or misplaced product key (certificate of authenticity) for Windows" http://support.microsoft.com/kb/824433
(this doc is specific to Windows 95, 98, Millennium and Windows 2000, but may also work for XP and Vista).
Sorry I couldn't be more help,
Darin MS