As I suspected, the file dates are over 9 years old.
GCC is written for Linux not Windows, that's why you will need additional support from Cygwin to help it run. With Linux, GCC is usually included with the OS files so it is there and ready to use without any installing.
Several compression/decompression programs for Windows can extract the files but I don't think Windows can do it natively. I think you will have to install 'Winzip', '7zip' or 'PowerArchiver' to do it, there are probably several other programs too as the format is very commonly used.
Brian.