There is no SIM card installed in the iPhone you are attempting to activate.

I updated my IPHONE 3GS from IOS 4.1 to IOS 6.1.3 and my phone was locked, when i try to unlock it with Itunes through Itunes software, it tells me that

There is no SIM card installed in the iPhone you are attempting to activate.

Please help me out as i can not afford to loose my phone.

I got myself into all these mess when i needed to install BBM, BADOO And WHATSAPP

MTN NIGERIA is the sim I Inserted.