Dotô jéka - tia marieta

Windows 7 professional is suppose to have windows media center as part of the system. It was missing so I put the original installation disk in and used the upgrade option. Now my system is not recognized as genuine, my activation key doesn't work and
my AVG firewall will not work. What do I do? I have looked all over the Microsoft website.

Dotô Jéka - Tia Marieta