It used to be I could view Chinese characters in Notepad, Notepad++, Wordpad, that kind of thing. It stopped working at some stage: all I got was little squares. Wierdness.
No amount of fiddling with encoding settings (particularly in Notepad++, which is replete with them) seemed to fix it.
Looking around the Control Panel's language settings didn't help either. You can install extra Language Packs, but the Chinese one is for Windows Enterprise and Ultimate only. I knew this couldn't be the answer because previously it had been working, but I was only on Windows Professional.
Following a tipoff I found via Google, from someone having similar problems, I tried this: create a new local logon; log on as it; log off again; go and try again.
Sure enough, that worked. Why? Well that's anybody's guess.