Facing TV Problems? Ask a TV Technician.
Hello and sorry you're having problems. It would appear you missed a screw here. Make sure you're also removing the screws around the HDMI, AV and power cord jacks on the TV- as well as any other which may not appear to be related. Remove the base stand as well. If the back still does not come off then shine a flashlight into ALL of the screw holes on the back of the TV to make sure you did not miss one. Once all of the screws are removed the back will indeed simply pull off.