ipad2,2 32G 3G+Wifi problem"No Sim Card Installed" !!

[niu]

Hi Guys,
Hope you are doing well, with problem in the title; I tried to change different sim cards, but still saying no sim card installed" I tried a different tray for the ipad and same problem exists.
My concern that when i eject and push the sim tray again, the ipad didn't detect any activity, I mean the error message"no sim" only appears when i switch on/off the data button from sbsettings.And not when i eject & re-enter the tray again!!

Things I have tried:different sim & tray.
-removed icaughtu pro, incase the force 3g is doing something but unfortunately still malfunction!
-reset network settings several times.
-rebooted ipad a couple of times.
-hard reset/power off .
Right now I am backing up my ipad and will restore to 5.1.1 ( i am on 5.0.1) & hope the problem would be solved( this is my last chance /try) that i hope restore would fix. Unless if Hardware problem exists; then I am stuck, ( no warranty) no Apple maintenace certified dealer in my country . Otherwise I have to seek someone who will be extra expensive for doing anything in ur ipad & hope wouldn't do any harm to any other parts

If someone faced such a problem and have a suggestion; I would appreciate so much.

Thank You for reading me,
B.Regards,

"Just restored and the problem still exists!" Anyone could help please.
Thanks