When WinVNKey is set up in Unicode character set, everything you type in will be Unicode characters. Whether a character appears correctly or not depends on the font you selected. You must select a Unicode font for Unicode characters. However, because the Unicode character set is very large (64 thousand characters), not many fonts support all of the characters. Typically a Unicode font supports only a subset of Unicode characters. Some fonts choose to support only the Latin-based characters. Others may support only Chinese, Japanese, or Korean characters.
Even though a font like "Times New Roman" supports a subset of Unicode characters such as Roman-based and Cyrillic-based characters, the latest version may contain more characters than earlier versions. For example, version 2.95 contains more characters than version 2.82. WinVNKey help should be readable with "Arial" version 2.76.
The following web site has a wealth of information on Vietnamese Unicode, Vietnamese keyboard drivers, Unicode fonts, and other useful links:
http://vietunicode.sourceforge.net
Microsoft used to offer a web site for downloading free Unicode Web fonts:
http://www.microsoft.com/typography/fontpack/default.htm.
You can still download some of them from the following sites:
http://www.microsoft.com/vietnam or more specifically here
Viet Unicode fonts from WinVNKey website
Phat Hoc Dao Uyen has some Microsoft fonts, including Arial Unicode MS font (14 MB compressed and 23 MB uncompressed). The Arial Unicode MS font file contains some 52,000 chars, including classic Vietnamese (Nôm), Chinese (Hán), Japanese, Korean, Pali-Sankrit (Pha.n), etc.
Unicode Fonts for Romanized Viet-Pali-Sanskrit (Pha.n) at Buddha Sasana and http://zencomp.com/greatwisdom/fonts/
Le Hoan Website: free fonts for VISCII, VPS, VNI, ABC, DHBK1 and DHBK2, Viet Unicode, etc.
http://unikey.sourceforge.net: free Unicode and Vietnamese keyboard driver Unikey and fonts