Download               Windows 7 Service Pack 1 Highly Compressed Download A: Remember, compressed files are meant to be stored in ZIP format. To change the extension of a file to ZIP or extract a ZIP file you need something like this: private void WIndows7Compress(string fileName, string zipFileName) { using (ZipArchive archive = ZipFile.Open(fileName, ZipArchiveMode.Read)) using (ZipArchive extractor = ZipFile.Open(zipFileName, ZipArchiveMode.Extract))