Hi Charlinhos,
Thank you for asking!
You have issues in installing Silverlight.
To assist you better, we need more information.
Which version of Operating System are you using?
To work with Silverlight installation issues, I would suggest you to refer to the site:
How to clean a corrupted Silverlight installation and then reinstall Silverlight
http://support.microsoft.com/kb/2608523
Disclaimer: This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows XP
http://support.microsoft.com/kb/322756/
**http://windows.microsoft.com/en-US/windows7/Back-up-the-registry**
http://windows.microsoft.com/en-US/windows-vista/Back-up-the-registry
For any Windows related issuefeel free to contact us.