With IE, you need to install language packs in order to display stuff right (although I'm surprised it's showing nothing at all, I'd have thought it would display incorrect characters).
You were obviously better with UTF-8 (since this worked before in FF and Chrome) but I'm guessing IE is not prompting you to install the language pack.
When I try and visit a Chinese site from my IE, I get a prompt (see attached image) which has an option to disable future prompts. I don't know how to undo this option (a quick Google has yielded no viable results) but I would guess this is the problem.
May be you could manually install the language pack?