my brother had one very similar to that, he had the pocket kitty! i dont think there's much info on them bc last i remember he said they arent really documented well... i believe that screen might be the death screen? If so, i think all you can do is just reset it. I remember my brother's pocket kitty was kind of glitchy and never wanted to restart properly though. Not sure how much of a help I can be since I'm not the one who actually owned it, but I hope you can fix your problem eventually! Its really cool to see someone else own this same kind of obscure virtual pet