The key was based on the computers hard disk's Volume Serial Number (8 characters) and additional data about the computer (5 bytes).
serial killer | The Chronicles of Narnia (TV serial) | Superman (serial) | Lucky Number Slevin | Reynolds number | Mach number | Flash Gordon (serial) | serial number | Random number generation | International Standard Book Number | prime number | Personal identification number | number | volume | Two in a Million/You're My Number One | Social Security number | Serial killer | Rikki Don't Lose That Number | Prime number | Premium-rate telephone number | Jackass Number Two | Henry: Portrait of a Serial Killer | Blackpool (TV serial) | Serial communication | Opus number | Number Girl | List of WTA number 1 ranked players | Lah number | Kill Bill Volume 2 | Erdős number |