This tutorial will walk you through the process of enabling Khmer Unicode on your Windows XP computer (if you need help installing Khmer Unicode on Windows 7 click here). First download
Khmer Unicode Installer for Windows XP
and then run the file – when you do you should see something like the following: 
Now click the “Next >” button as shown in the picture. 
Click the “Next >” again (if a box telling you that the directory does not exist pops up, just tell it to create the directory). 
Now click “Exit” (it is possible the “Windows File Protection” box might pop-up before you can click “Exit”, if this occurs, go to the next step to deal with the “Windows Protection” box and then once you are done, click the “Exit” button on the Installer window. 
When this box pops-up click “Cancel” 
When this box pops-up click “Yes” Now go here and download the latest Khmer Unicode Install Program (currently it is version 1.2.5) and once it is finished downloading, run the program. When you run it you should see something like the following: 
Click “Next” 
When this box pops-up click the “Complex & kbd” button (this can take a few moments to install, so please be patient). It is possible that you will need your Windows XP cd at this time – so if you are asked for it, please insert it into your cd-rom. 
When the text “Complex script enabled/Keyboard layout added.” appears click the “Close” button. 
To finish off the installation, click the “Exit” button. 
Now you should see a new button in the lower right corner of your screen saying either, “EN” or “CA”. When you want to type in English, make sure “EN” is showing, and when you want to type in Khmer Unicode, make sure the “CA” is showing. To switch between the two languages, you can click on the button and select (like the picture above shows), or you can press the “Alt” key and the “shift” key which is on the right hand side of your keyboard (if you press the “shift” key that is on the left hand side of your keyboard it will not switch). Enjoy!
Now click the “Next >” button as shown in the picture. Click the “Next >” again (if a box telling you that the directory does not exist pops up, just tell it to create the directory). Now click “Exit” (it is possible the “Windows File Protection” box might pop-up before you can click “Exit”, if this occurs, go to the next step to deal with the “Windows Protection” box and then once you are done, click the “Exit” button on the Installer window. When this box pops-up click “Cancel” When this box pops-up click “Yes” Now go here and download the latest Khmer Unicode Install Program (currently it is version 1.2.5) and once it is finished downloading, run the program. When you run it you should see something like the following: Click “Next” When this box pops-up click the “Complex & kbd” button (this can take a few moments to install, so please be patient). It is possible that you will need your Windows XP cd at this time – so if you are asked for it, please insert it into your cd-rom. When the text “Complex script enabled/Keyboard layout added.” appears click the “Close” button. To finish off the installation, click the “Exit” button. Now you should see a new button in the lower right corner of your screen saying either, “EN” or “CA”. When you want to type in English, make sure “EN” is showing, and when you want to type in Khmer Unicode, make sure the “CA” is showing. To switch between the two languages, you can click on the button and select (like the picture above shows), or you can press the “Alt” key and the “shift” key which is on the right hand side of your keyboard (if you press the “shift” key that is on the left hand side of your keyboard it will not switch). Enjoy!