Modify Google doc viewer/ any doc viewer

Hello, We need a doc viewer (you can modify any doc viewer) so that user can't download documents. We are uploading documents and need users to view them on our site NOT download them. Google doc viewer shows two popup buttons which allows you to download document being viewed. We need it for doc, docx, ppt, pptx, pdf, xls,xlsx If you are able to do it, you need to cordinate with our programmer to integrate it in Yii (we have already Yii app created where we are uploading docs).