As to view flash content on Websites you need to have flash player plug-in installed in browsers, similarly to view websites developed with Silverlight, you must have Silverlight installed on your Computer as well.
It is necessary to know, for any user what version of Silverlight installed on his Computer so that a website powered by it might mislead a user to install the latest version of it, which user already has.
Ways to find the version of Silverlight installed on Computer
1. Visit this official Microsoft page in any browser, this page detects and shows Silverlight version, if you are using an older version, it recommends to install the latest one.
2. Another way is checking Silverlight’s installation directory in Program Files.
Navigate to C:\ Program Files\Microsoft Silverlight, here you can see it’s version number.
3. Using registry: Open Registry Editor by typing ‘regedit’ in Run command and navigate to HKEY_LOCAL_MACHINE\Software\Microsoft\Silverlight, and view the version entry on the right pane.
4. Using Firefox:
Open Firefox, Tools>Add-ons> select Plug-ins tab and select Silverlight plug-in to know its version.
5. Using Chrome:
Open Chrome, type about:plugins in address bar, you can see the Silverlight plug-in version.
6. You can also find Silverlight version by opening add or remove programs in Windows XP or Programs and Features in Windows 7/8 and select ‘Microsoft Silverlight‘ to view the version.