I use WindowsXP Pro in English. I share with my wife and we’re always able to see and type in Chinese, even on a BBS.
Go to the control panel and open Regional and Language Options.
Click on Languages and install all the supplemental language support.
Click on Details and install all the additional Chinese languages and keyboard arrangements/input methods that you might want to use.
If you want to be able to type Pinyin, download Microsoft New Phonetic IME 2002a. Highlight and click properties. Go to Keyboard Mapping and select Hanyu Pinyin.
Go back to the Regional and Language Options Box and click advanced.
For the Language for non-unicode programs, select Chinese (Taiwan).
Select all the Chinese code conversion tables from the box below.
After doing all this, we’ve never had any problems. The one thing to watch is, when the box pops up saying ‘you must restart before the changes will take effect. Do you want to restart now?’ I had to restart immediately, other wise some of the changes didn’t stick.