If you can't copy files that are bigger than 2 or 4 GB, usually HD movies and such, on to your USB key, it's usually due to the file system the USB key is formatted to.
Zip files are compressed archives containing documents, images, folders, basically any type of files on your computer. We create them to save space and make them more practical for sending via email or file sharing services.
A less known but very useful feature that works since Windows XP has been released. You can easily rename a bunch of files in a matter of seconds, let me show you how.