You wish to delete a participant from the system, but you receive a message like this one:
Participant 'Firstname Lastname' has orders in system and cannot be deleted. Please delete these orders first: #100
You cannot delete the participant because they have orders attached. If this occurs, please note the order number in the error message and go to Reports -> Orders. Then locate the order # and click on the 'view' link next to it. Scroll down to the very bottom of the order and hit the 'Delete Order & Participants' button to delete both records, the order and participants. If you prefer, hit the 'Delete Order' button and then go back to People -> Participants to delete or edit the participant.