A: Creeper cards say “You can’t win if you have this unless the Goal says otherwise.” This means that having a Creeper in play in front of you prevents you from winning whether it is attached to one of the Keepers needed for the Goal or not.
Creepers occur in many versions of Fluxx, but only in a relatively few versions do they attach to specific Keepers. So the question of attachment does not affect the general behavior and limitations of Creepers.
This is sort of the corollary to this question: If a Goal requires a Keeper and an Attaching Creeper…