Lost or misplaced product key (certificate of authenticity) for Windows

This article describes how to find or replace the product key (or certificate of authority) for a Microsoft Windows guest operating system in Virtual PC.

The product key for a Microsoft Windows guest operating system is included with each copy of Virtual PC. Use the appropriate method for your version of Windows to find the product key.

Microsoft Windows 95 and Microsoft Windows 98

The product key is included on a separate card that is included with the corresponding Windows manual. For some versions of Virtual PC, the product key is located on the front cover of the manual.

Microsoft Windows Millennium Edition

The product key is included on a separate card that is included with the corresponding Windows manual.

Microsoft Windows 2000

The product key is located on the back of the Quickstart guide.

Lost product keys

If you can start your guest operating system and that system is Windows 95, Windows 98, or Windows Millennium, follow these steps to find your product key in the guest operating system:

1. Start Registry Editor (regedit.exe).
2. Locate the following key in the registry: HKEY_LOCAL_MACHINE\Software\MIcrosoft\Windows\CurrentVersion\ProductKey
3. Write down the value of the key.
4. Quit Registry Editor.

For all other guest Windows operating system product keys, contact Microsoft Product Support. To locate the phone number, visit the following Microsoft Web site: