Regarding Revo, I've used the program many times with success but would make this point:
Take care if using the advanced cleaning (registry) if you have more than one program from "a particular supplier". I used it to remove a program and it promptly messed up one of their others. Never tried it on MS Silverlight but as MS figures throughout your computer it could cause an issue. It's probably a bit like registry cleaners, you might use them fine for years then suddenly they get it wrong.
Always pop back and let us know the outcome - thanks