Go to User CP -> Edit Options
and change "default thread subscription mode" to "do not subscribe" or "no email notification" depending on what you want.

For the threads currently subscribed, Go to User CP -> List Subscriptions
Click the check box in the title which has the same effect as clicking the check box in each subscription. Then at the bottom, pick whatever you want from the drop-down list.

To change your email,
Go To User CP -> "Change email and password"

I'm not sure how much of this can be done with your account in its current state. If you can't change your email, PM me with a new email address and I will change your email address. Then you can use that resend activation email link to get the reactivation email.