You need to get a file compressor known as WinRAR to extract them. NDS and GBA emulators like NO$GBA and VisualBoyAdvance won't read them unzipped as .RAR files. So WinRAR fixes that for you! I have the file if anyone wants me to share the install with you!
its a free download from hundreds of different places, why would anyone need to get it off another person?