If your device is still new, and under warranty, I would suggest you contact Samsung or your service provider as you don't want to do anything that will void that warranty.
If it is out of warranty, then you can then ignore that worry. Have you tried restarting the table since the changes? You may want to try using the reset button to do a "Factory Reset" of the device and see if it will move past the issue. There should be a pinhole either on the exterior of the device or where the sim and sd cards go. Us something like a pen or similar item to depress it and try to do the "Factory Reset". Do not use an actual pin or other sharp object as it could damage the device.