I now understand. I had to go to Start / Control Panel / Regional and Language Options:
from there, Languages tab, and select "Install files for complex script and right-to-left languages". It asks for the XP cd, and you give it ot it then it wants to reboot.
I'm not sure THAT was necessary, but it was part of the formula anyway,
Ok, then in that same "Regional and Language" dialog, on that same Languages tab, I chose "Details...", Settings tab in the dialog that comes up, Add..., then choose an arabic keyboard layout.
Click OK. You should now have an EN
language selected in your taskbar.. if you click it you can choose AR
now and you can type arabic!
woot!