Zip (compressed) files are a way to send multiple files at the same time by combining into one file. This also leaves the original files untouched. There are many types of zip files and 7-zip program opens them all. 7-zip can also create .zip and .7z compressed files. Download the program at http://www.7-zip.org/ select the 64bit if that doesn’t work on your computer then select 32bit version.  Install with the default items selected and open it. From the 7-zip program select ‘Tools” > “options” > “select all” > “ok”. Now in my computer you can right click a zip file and uncompress to a folder of the same name. You can also select (highlight) multiple files > right click one of them > and choose add to zip.