You can download the Pokemon N64 PC emulator from here. You can download n64 emulators for Windows, Mac, and Linux. These emulators can run any Pokemon ROM developed for n64.
Download Pokemon N64 PC emulator
Download the emulator according to your system from below.
Pokemon N64 Emulator for Windows
Pokemon N64 Emulator for Mac
Pokemon N64 Emulator for Linux
You can get the n64 ROM from Pokemon N64 ROM