Manually locating the Windows Vista product key from the registry is next to impossible as its encrypted. Luckily, a number of free programs exist to help find product keys.

1. Choose a free product key finder program that supports Windows Vista.
2. Download and run the key finder program. Follow the instruction.
3. The product key should be formatted like xxxxx-xxxxx-xxxxx-xxxxx-xxxxx - five sets of five letters and numbers.
4. Write this key code down exactly as the program displays it to you for use when reinstalling Windows Vista.