Hi Penny,
I am totally computer illiterate but am grateful for the many responses many intelligent people have posted. From them I conclude that at one time Microsoft was selling ebooks but they are no longer doing so. When you turn on your computer, there is an outside app or program that is asking to connect your computer to that site. Since the site is no longer active or certified up to date, Bitdefender blocks it. No one has been able to identify the outside app or program but it apparently is not Microsoft itself; most people say it is harmless.