Hi AndrewCollinsTC,
1. Do you receive any error message when the Microsoft Silverlight update tries to install?
2. Have you made any software or hardware changes on your computer prior to this issue?
3. Did you follow the steps suggested in the previous post?
Please provide us more information regarding the issue so that we can deliver you the required assistance.
Who marked this as an answer? Someone without a brain?
Please remove this as an answer!
By the way, what sort of answer are you expecting for question number 2? "Yeah I've installed an antivirus and a competing Office product"?
If you meant to ask if the OP had made changes recently, then say so! As it is, even installing Flash 2 years ago would count.