First, go to your User Control Panels
(user cp), then click on Edit Options
. The 6th field down allows you to choose Email Notification
, click NO
You can then click on this link to remove all of your subscribed threads:
(You can also find it on the first page of the USER CP entitled "view all subscribed threads", from there you would be shown the threads and the above link to unsubscribe.)
It sounds like you already did the first step RweTHEREyet, but I'd double check just to make sure! Then click the above link to "unsubscribe" to all of the threads you were set to recieve notification on before you it turned off. That should do the trick for you.