I need to direct you to other websites to download Parasite Eve. There are many options in my links. You could also try these helpful Google searches:
Once you download Parasite Eve (or its sequel), a PlayStation 1 emulator is needed to play it. To play 3rd Birthday, a PSP emulator is needed. On my emulators page, you can find the best emulators for Windows, Android, and iOS. If you need help using emulators, check out my emulation help site: Video Game Emulation for Newbies.