On-Screen Keyboard in Windows XP to type in Arabic:
First you must have the Arabic Language installed. If you don’t, see this post to install it installing-arabic-language-in-windows-xp/
After you install the Arabic Language You can find the On-Screen Keyboard by going:
> Start
> All programs
> Accessories
> Accessibility
> On-Screen Keyboard
When you press shift button you will get this:
See more info:
http://www.microsoft.com/enable/training/windowsxp/usingkeyboard.aspx
Arabic Tools 
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