If you weren't ED anywhere, which I take to mean that you did not put in an ED app at all, you do not HAVE to withdraw all of your apps. Not paying a seat deposit by the deadline will effectively withdraw your app.
That being said, if are 100% sure you are going to a school that you have been accepted to, you SHOULD withdraw your other apps to allow the waitlist to get moving. You don't have to, but waiting until April when you're sold 100% on a school in December does prolong the wait for someone else.