Block all of profile edit or specific fields? You could set fields as Read Only so they can only be supplied via registration and then cannot be edited. CB Conditional can conditionally make tabs and fields editable or not. CB Privacy can as well to a degree, but not as much as CB Conditional. You could try using the Layout features of a field and use IF substitutions to try and condition the edit display, but that's purely visual and won't block server save behavior.