If I understand correctly, you turned off the option to turn notification on when you post to a topic. (Man, that's lots of emails!) If this is so, you won't receive notifications on new topics you post to, but you're still "subscribed" to all the previous topics you've posted in.
If I'm on the right track, go to your profile, then "Notifications and Email" link, then look under the table titled "Current Topic Notifications". If you have a list there, that's what you want to delete. You can checkbox each topic selectively and click the Unsubscribe button or you can check the checkbox in the heading row to check all the checkboxes to unsubscribe to everything at once. I haven't had more than two subscriptions, so I'm not sure if it starts running into multiple pages if the list is long. If there are multiple pages you'll have to Unsubscribe everything a page at a time.
If this doesn't help, post back here and I can look into it more closely.
By the way, when you visit the board you can click the link at the top of the page "Show new replies to your posts" to get a list of topics you've posted to that have unread replies. Also, in the board indexes topics you've posted in have a yellow folder.
The email feature could be nice, but this board is so high traffic that the emails will come too fast.
