Strange issue with usergroups

[lafsunlmtd]

Hey all! So I am having this issue with usergroups. Basically what happened is I had some promotions running with a certain user group. Well, I recently deleted the promotion and the usergroup. The problem I am having is that now when anyone registers for the site, they automatically get put into that user group that was deleted. I haven't modified the files at all, so I know it's not in the code. I actually looked in register.php and the $newusergroupid still = 2. So any time someone registers it automatically assigns them to usergroup 15 and I am bashing my head against a wall trying to figure out why. Has anyone experienced this before? It just started happening out of the blue. Any help would be appreciated. Thanks!