If you create replicas then the Key, if it is a Virus or Spyware Key will not be gone? Its sort of a risk you'll have to take to do it. It you save your entire registry onto a CD, or maybe just the Files in it which you are editting then they won't be there to manifest themselves again. That would be another way if you have a CD Writer.
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.