I read in the Internet that Orbit Downloader can download Silverlight video but I would say do not try it. I t installer something calls Delta software and Add-ons to your IE. That is not just yet, it will prevent your IE 10 from working in Windows 8 once you uninstall it.
You need to delete the user and create the new one to get IE running again.
All the best if you think you still want to try it.