There are 3 types of licenses :

• OEM - Only allows you to do a clean install
• Retail - Allows you to do an upgrade of existing OS
• Volume - Also known as the corporate version

The license type is contained in the install file X:\i386\setupp.ini :

Pid=55034000

The 5 first digits of the Pid says what license it is, and the last 3 digits says what license cd-key it accepts.

• OEM - Pid=82503OEM
• Retail - Pid=51882335
• Volume - Pid=51883270

Note it is possible to interchange the license and the cd-key which is required. Ex. one could create retail license accepting OEM keys Pid=51882OEM.

Note that one cannot change an OEM/Retail version to a corporate version by just changing the Pid. There are other differences in the files included and you will still have to activate it with a corporate key.

Credits TheTechGuide.com