Hi Victor,
Can you run Media Center? If you can, click "Help" and then click "Registration Info". It should show that it is registered to you.
If you cannot, reinstall the latest version of Media Center (available here), then restore your license.
When you write back, please take the time to give us details: exactly what steps you are going through, and exactly what is breaking.
I know this is difficult for you, but we need the information to find out what is going wrong.
Thanks,
j