To use MelonDS, you need to have a nand.bin file. Without it, the emulator will not be able to function properly. The nand.bin file can be obtained from a real NDS console by dumping its NAND memory using specialized tools.
Avoid public NANDs. They are a legal gray area, often unreliable, and may be bundled with malware. Always dump your own. nand.bin melonds
"An error has occurred. Press and hold the Power Button..." (The DSi Blue Screen) To use MelonDS, you need to have a nand