Hi and welcome to the forum @Anonymous User,
For computer users running Windows 8.1 (or higher), it's recommended that you install the NOW TV Windows app. As it does not require 'Silverlight' and provides you to view the NOW TV service at HD resolutions.
After installing the new NOW TV Player app, it is advisable to completely remove the (now redundant) Silverlight plug-in from your computer. It is also advisable to remove any unnecessarily browsers you may have had to install in order to view the NOW TV service in the past.