This allows you to set your own personal pin number for added security. When the pin number is enabled the ANGEL LCD TM is locked and incapable of firing to prevent unauthorized use. We recommend you use this security feature to protect your investment and others from misuse.
Caution: Once the pin number is set should you forget your pin code, and cannot unlock the ANGEL LCD TM . You must contact WDP Ltd, and have to hand your unique serial number, which can be displayed by pulling the trigger when the ANGEL LCD TM is locked or in safe mode. You must also provide verifiable proof of purchase and identity before we will issue you a unique unlocking code to your ANGEL LCD TM. When entered this code allows you to enter a fresh pin number. You may incur a small administration charge for this service.
^^Taken from the manual found on WDP's site, found here:
http://www.wdp.tv/manuals/lcd_manual/
I think you may need this later on, you wont have as many questions
Try askin the guy you bought it off of what he set the PIN number as this may avoid having to go through WDP