I didn’t go right into the details before since they’re quite complex.
IE and Windows use the same language settings. If Windows does not have support for Chinese installed then IE cannot display Chinese characters. When IE installs a language pack it’s actually installing a Windows language pack. You can verify this by looking in the Regional Options in the control panel.
As a test, try the following:
Look in Regional Options in the control panel and verify that Traditional Chinese is not ticked in the list of system languages. Then visit this page that contains some Traditional Chinese text in Internet Explorer. IE should prompt to download a language pack at this point (if not select View/Encoding from the IE menus and select Chinese Traditional (BIG5)). Let the language pack install and you’ll then be able to see that the Chinese box is now ticked in the control panel applet. All applications can now access the data contained in the Chinese language pack.
Included in the language packs are things like rules for formatting dates and currencies, fonts for displaying the written characters, input locales and keyboard definitions etc. If you need to use a foreign keyboard you can install only the keyboard definition from a language pack, but you may find extra characters do not render correctly on the screen without the rest of the it.
You’re correct to say that there is no big “Be Chinese” button in Windows, but you can set Chinese to be the default system locale. The effects of this are not immediately obvious, but any application that uses the Windows API to format its date/time or currency output will begin using Chinese formats and characters. To be really Chinese you’ll need a localised version of Windows. This means, basically, that Chinese is the default selection for the system locale and all of the Windows text, helpfiles, dialog titles etc will have been translated. This page lists all available localised versions of MS Operating Systems (By way of translation 1033 is the LCID for US English).
Most applications, browsers included, depend on the Windows language packs for displaying non-standard characters. In the end only a very rare few have their own system of fonts or make minimum use of the Windows GUI API. This behavior is usually restricted to things like CAD packages that may need to enter text as simple vectors for output on devices like plotters. As far as I know all of the major browsers use Windows fonts, input locales, codepage mapping and other services to render pages. If Windows ain’t got it, they can’t do it.
In my original answer I was trying to point out that there’s really no hard and fast default for US Windows. A fresh-from-Microsoft copy of English Windows will select US English as its default, but will also offer the option to change it on install. OEM provided versions of Windows may change this. Pre-installed copies of Windows may be different again. I realise that this probably wasn’t the answer you were looking for, but I figured since it was in GQ I’d try to give a broader background to it.