1. Download and launch the Microsoft Silverlight Fixit tool (see either of the links in References). Click 'Next' to move through the troubleshooting wizard to scan for and resolve Silverlight problems.
2. Download and install the latest version of your Web browser software from the developer's website. This process improves compatibility with the newest versions of Netflix and Silverlight; it also replaces any browser files that may have been deleted or damaged.

3. Launch your browser without any plugins or extensions running to see if this solves the problem. Use your browser's built-in add-ons manager to disable extensions, paying particular attention to add-ons related to video playback and streaming that may be interfering with Silverlight's operation.
4. Click 'Control Panel' from the Start menu and choose 'Uninstall a program.' Select Microsoft Silverlight and choose 'Uninstall' to launch the removal process. Restart your computer, load Netflix and begin the Silverlight installation from scratch.
5. Download and install the latest definition files for your anti-virus and anti-spyware programs. This should be enough to ensure the Silverlight upgrade is not being blocked or scanned by a security tool that considers it to be a threat.
6. Empty all of the Netflix-related cookies stored in your browser by visiting the customized URL listed in Resources. This process removes any temporary cached data that may be affecting the Silverlight upgrade process. Restart your browser and attempt the Silverlight upgrade process again.