okay, you downloaded malware. Does your desktop at least have the recycle bin icon? If so, as I've seen a virus that does this quite often, your files are still there. Boot into safe mode, and click recycle bin so it opens. Hit the alt key, it will bring up a menu at the top. Click "tools" then select "folder options". Go to the "view" tab and select "show hidden files, folders and drives" and save it. Your files and desktop icons will re-appear as opaque, as the malware made the files hidden. You can back up the data now. The easiest thing to do, since in most cases it contains a rootkit, is to back up and reinstall windows. You can change the files back from "hidden" by right clicking folders and unchecking "hidden" in folder properties.