Hello Lorraine,
I use two computers with Windows 7 and one with Vista on a daily basis and I am not sure if I would miss Silverlight if it were gone.
I will disable it on all three computers tomorrow and post any changes I notice but for now I am posting some of the technical information needed to run Silverlight along with a link to much more information.
In order to view all the multimedia content and animation in all websites, you should have these add-ons installed:
Adobe Flash Player 10 ActiveX - for Internet Explorer
Adobe Flash Player 10 Plugin - for non-IE browsers
Java Runtime Environment
Microsoft Silverlight
I have listed system requirements for Microsoft Silverlight and associated technologies below.
Windows
Operating System: Windows 7, Windows Vista, Windows XP Service Pack 2
Intel Pentium III 450MHz or faster processor (or equivalent)
128MB of RAM
Silverlight is an application framework for writing and running rich internet applications, with features and purposes similar to those of Adobe Flash. The run-time environment for Silverlight is available as a plug-in for most web browsers running under MS Windows. While early versions of Silverlight focused on streaming media, current versions support multimedia, graphics and animation, and give developers support for CLI languages and development tools. Silverlight is also one of the two application development platforms for Windows Phone 7.
http://en.wikipedia.org/wiki/Microsoft_Silverlight