I am using Windows 7 and someone who is not in my Windows Messenger contact list has been harassing me with sexual requests. This is most irritating and I had searched everywhere for ways to totally block this person from contacting me but to no avail. Each time my Messenger goes online, this person will message me, be it day or night.
How can I either block this person permanently, or prevent anybody who is not on my contacts list from chatting with me?