I have an Android KitKat dual SIM phone, fitted thus:
Slot 1: Virigin - calls, texts, 3G. Slot 2: Empty.
The main screen shows:
No SIM card
I can make calls and use 3G fine, but "No SIM card" and "EMERGENCY CALL" annoy me.
Nothing in Settings affects it.
It's a dual SIM phone - they will go away if you put a SIM in slot 2. Alternatively you can fix the problem by buying a single SIM handset.