When I turned on my new 3DS, it shows an error like ”an error has occurred. Hold down the POWER Button to turn off the power, then turn it on and try again. For help, visit support.nintendo.com”.
Here are the solutions..
Fix 1: Remove SD card
Remove the SD card and so the system boots normally or format the SD card.
Fix 2: Update Nintendo 3DS
Try to apply the latest system update. That will help to improve General system stability.
Fix 3: Remove and reinstall WiFi adapter
Open Nintendo 3DS and find the WiFi adapter,
Remove the WiFi adapter and reinstall it.
Fix 4: Use Nintendo 3DS Download Repair Tool
If the error occurs during a game or application (downloaded from Nintendo eShop) is on, check the game or application using Nintendo 3DS Download Repair Tool.
Fix 5: Deleting Extra Data
If the error occurs when you play a specific game, delete the extra data of that game.
Note: If the issue is not fixed, the system 3DS needs to be repaired. So send the system to Nintendo to check what is wrong with 3D.