Completely locked out of my iphone 6?

If i replace the motherboard and the sim card on my iphone 6 will that make it as if no one ever used or had an icloud account on it? I'm lock out of it. I already factory rest it but it still asks me for my itunes/icloud account. I forgot my password. Please help. Its been 2 weeks… Oh and how do i make sure i buy the right new motherboard for my iphone 6. Please and thank you!

If you replace the motherboard, you won't be asked about your previous Apple ID. You can create a new one and activate with it. But if the problem is iCloud lock, you can try the bypass instead of replacing the motherboard which will void your warranty. If you need help with your issue, mail me for more info.

Can you try to register for a new itunes/icloud account!