If it's computer controlled, you'll need to get the designer mode password from Steve, then use (IIRC) the Race screen (ctrl-F2) in SM mode to delete them. That or send your DB to a volunteer with the designer mode pw to repair it for you. Note that all designer mode lets you do is "see" computer-controlled races.
If it's human controlled (i.e. shows up as a choice in the race pulldown), then all you need to do is go to SM mode then open the ctrl-F2 screen. There should be an option to delete the race.
Note that deleting a race is complex and not done very often, so there's a good chance it's buggy, e.g. leaving "ghost" sensor contacts lying around that you can't get rid of.
John
