You can download and install the special version of Silverlight for Xfinity. Read this article for the instructions.
Ensure that you use 32-Bit Internet Explorer 10 to install Silverlight 5.1.10516.0 version
Go to the desktop mode and click Internet Explorer on the task bar or launch IE 10 from the Start Screen and select View on the Desktop.
Hope this helps.
Please revert for any clarification.
Thanks and Regards,
On a windows computer, running the official Windows 8, 64 bit software, silverlignt crashes in the XFINITY site. No problem running Silverlight for NETFIX. Any updates/ Reported the problem in the pre-release version. someone suggested I go back to Windows 7. I am looking for a more enlightening response.