That's what happened to me. If tightening the screws in the tama doesn't work, you need to replace the whole screen. My topic is down a little bit on the What happened to my Tamagotchi? topics page, and it's called What Happened to my Tamagotchi's Screen? I know our tamas are different versions, but the v1-v4.5 all have the same exact screen, so you could use the screen from any of those versions to replace yours. And there's a guide in the topic, which explains how to replace the screen, and it's super easy to understand. One good thing about having to change the screen on a tama, you can change the background at the same time! Hope your tama starts working soon!