Q: After upgrading to IOS7 showing no sim what is the remedy?

Hi..

Try the troubleshooting steps here > iPhone: Troubleshooting No SIM

apple care walked me through this.

remove SIM card-with home button down, tray is on left side of ipad-can use small paperclip for eject button in hole next to card tray

settings/general/reset/reset network settings

reinstall SIM card

so much easier if apple care would post things like this themselves