Mainly there are two ways by which you can activate the ancestry kit. As most of the time, you forgot to do the registration on the site of the ancestry. Then, in that case, you can easily activate your DNA kit of the ancestry just with the help of the activation code. This activation code is printed on the tube and you will see the proper guidance on the back of the kit. But there is no activation code on the kit then you need to replace that kit which is totally free of cost. So there is no need to worry about the registration.