The ZIP file format was developed by Phillip Katz and has become a de-facto standard for file compression since he released the small command-line utilities pkzip and pkunzip in 1986. Windows XP provides built-in support for the ZIP file format. However, because prior Windows versions did not support ZIP files, many users installed third-party file compression utilities such as WinZip and continue to use them with Windows XP.
Windows XP treats ZIP files more like folders, where file compression utility programs tend to treat ZIP files more like files. If you are using Windows XP it is important, therefore, to be able to determine whether or not a third-party file compression utility program is installed. If you are using the Windows XP built-in ZIP file support it is also important to understand that you cannot perform many "folder-like" operations when it looks like you are working in Windows Explorer.
If a third-party file compression utility such as WinZip is NOT installed the File Type will be identified as "Compressed (zipped) Folder" and the icon will be a yellow folder with a zipper on the left side. Right-click on a ZIP file, select Properties, and note the file type and the name of the application the file opens with. If a file compression utility is not installed then Type of file will be "Compressed (zipped) Folder" and Opens with will say "Compressed (zipped) Folders" (the last part might not be visible).
If you determine that a third-party file compression utility program is not installed then extract a ZIP file as follows:
On a Windows XP system where a third-party file compression utility is not installed ZIP files are treated as a special kind of "folder," specifically a Compressed (zipped) Folder as indicated by the file type discussed above. If you double-click a ZIP file on this system Windows XP will open the ZIP file in a familiar looking Windows Explorer window:
Look closely at the address bar, at the top level it shows the name of the ZIP file, NOT the name of a folder. However, if the ZIP file contains a directory tree of one or more sub folders (as many do), when you progress into the sub-folders the address bar will look much like any other folder. Make a point to have the Explorer Bar open in the left pain, and to use Details view so that you are reminded that you are navigating within a ZIP file, NOT a "normal" folder. When working within a Compressed Folder you will not be able to perform normal folder-like activities such as creating new files and folders because you are actually inside a file.
While Windows XP has built-in support for the ZIP compression file format, many users (including school computer lab administrators) install third-party file compression utility programs. Common examples are WinZip and PowerArchiver.
If a file compression utility such as WinZip is installed the File Type will be identified as "WinZip File" or something similar for a different compression utility program. Right-click on a ZIP file, select Properties, and note the file type and the name of the application the file opens with. As discussed above, if a file compression utility such as WinZip is installed, it will say so.
Most file compression utility programs will have an Extract button on the toolbar. Alternatively, look for an extract menu item in the Actions menu. The Extract dialog should look familiar: navigate to the drive and, optionally, directory (folder) where you want to extract the files.
