A:AnswerI had this problem once. From the User Manual: "Unplug the power cord, wait 60 seconds, then plug the cord back in and turn on your TV". This worked for me.
A:AnswerYou must have the Caption on. Go to settings and turn them off. It’s the setting for like a bar or a display with sound off to allow people to know what is on without volume on!
A:AnswerI had a problem with apps stopping because it said the TV was full so I reset the TV and added a thumb drive to the USB port on the back. I don't know if this would help you, but if you have one laying around it's worth a try. Good luck!
A:AnswerYou can purchase the replacement remote model NS-RCFNA-21
Also, you can download the Amazon Fire TV app on your smartphone to control your TV over WiFi.