Deleting Server Files / Disable Links

Cost center, FDM and Fund were links on the Core Concepts webpage (http://workday.yale.edu/workday-core-concepts) and I deleted them from the list. (I did not disable the link before I deleted the items from the list - I see now, that I should have.)

Why can’t I disable these links?

http://workday.yale.edu/sites/default/files/files/Cost%20Center(1).pdf

http://workday.yale.edu/sites/default/files/files/FDM(1).pdf

http://workday.yale.edu/sites/default/files/files/Fund(1).pdf

I went into the Server and renamed these files to:

• Cost Center (1)-outdated.pdf, FDM(1)-outdated.pdf, Fund(1)-outdated.pdf

But the above links still worked?  Why?

Then I went to the server and deleted these three files, and the above links STILL work - why?

Is there some redirect that I need to disable?  Am I not going to the correct file server?  How do I prevent people from seeing these pdf files if they have the above links?

Thanks

-Kathi