Uh, I don't know what you downloaded or who you are afraid of that might see what you did, but I have some bad news for you. Deleting the file from your library is not completely correct as far as erase the evidence. The file name you downloaded is in your .bak file or .ntuser file or in a few other locations and without specific computer knowledge you will not get it all out. Just be careful in the future. The 'file" itself is mostly gone.