Removing duplicate files

Edward,
We apologize, could you please provide us the screenshot of the error message you are getting? Make sure that the files which you would like to delete should not be a windows folder. Let us know the exact path you would like to remove. Awaiting your reply, thank you!

using PC tune up to clean computer. I have major duplicated files using up most of my my space. When I tried to delete it says "I do not have permission as trustedinstaller". How do I get permission and delete duplicate files?

Ed, For your info, just in case that you are unaware, you can post the screenshot (http://avgclick.me/getscreenshot) here in your topic. Click on 'Answer' & then click on the 'Image' [mountain symbol] & follow the instructions. 
AVG Guru

I went into PC Tune to find PC health showed one problem. Went to fix and said “low disk space”. Went into duplicate finder scan showed 275.72 MB. Most of my space is used up. Noticed in program files I have “Windows” and Windows Old. Tried to delete files C Windows Win SxS backup
MSIL_presentationframework.royale_31bf3856ad364e35_4.0.10240.16384_none199a9ecf1333757c

Edward,
We apologize, could you please provide us the screenshot of the error message you are getting? Make sure that the files which you would like to delete should not be a windows folder. Let us know the exact path you would like to remove. Awaiting your reply, thank you!