Inserting/removing your SIM card can help with activation issues/errors, browser connection problems or a blank/frozen screen.
Don't attempt to insert the SIM card while the device is powered on. Doing so may harm the SIM card and/or the device.
Ensure that the device is powered off.
From the left side of the device (display facing up), remove the SIM/SD card tray.
Use the insertion/removal tool (or a paperclip) to unlock the tray by inserting it into the provided slot then remove the tray.
Using the side of the card tray labeled "SIM", insert the SIM card into the tray (gold contacts facing down).
Ensure the card fits into place.
Turn the tray over then insert the card tray (gold contacts facing down).
Press in on the tray to lock it into place.