So I eventually tracked down what my phone is, and Samsung's troubleshooting is useless.

My phone decided to tell me the battery was low earlier so I turned it off to stop it beeping, however having got back to my house and went to plug it in I discovered it was showing a picture of a rather outdated rounded mobile phone with an arrow pointing into the top of it. It won't turn on even if I plug it in. Anyone know what's wrong with it? My instant reaction was to remove the battery to reset it like I used to do with my old Nokia 3410 but I'm not sure how safe it is to do that with modern technology.

EDIT: it's just fixed itself, not sure how or why, but it has.