Here is the additional instruction for the Lao font. In order for the programs to use the font, you need to put it in the directory called "WINDOWS/Fonts", along with other fonts. The Lao font is called "Lao New Light". You may have to reboot your computer to allow the new font to be initialized for the programs that you run.
For example, when you use the Microsoft Word, you can type in numbers and letters and change to Lao font to display the equivalent translation of the numbers and letters you typed.
You may check to see if you have the Lao fonts installed by clicking here.