Default [Q] No network available on unrooted s4

I bought a second hand samsung s4(a few days old) from my friend...after inserting my sim in it, it isn't showing any network signals...when i looke in settings for network operators and selected automatically choose preferred networks, it shows "Can't connect to this network right now please try again later"...have removed and reinserted my sim in it but still no benifit...Have searched about my problem and found a related problem with another devices (s3) and it told them to place an EFS folder in root if you have backup but it was for a rooted phone and mine is not...So, Please help me