Hello everyone!
I have replaced a complete motherboard because my phone was damaged by falling off my jacket's pocket at 150 mph... , from the remaining 8 pieces the motherboard survived.., so bought another one with a not working one and put it in there.
The same no service and no sim card detection problem appeared on ios6.1 and for me the easiest solution was to go to:
Phone( where favourites, recents, contatcs,keypad, and voicemail are), and select the voicemail then it ll realise something is not okay, and ask for sim card unclocking :)