Don't know whether B23 worked before or not, and the error was just "Cortex Command.exe has stopped working"

Do a clean install on a test computer from a newly downloaded file, and post results.

Hopefully this will work:

-uninstall CC from both computers (delete anything and everything);
-install CC on the xp computer. Does it run? If yes, go to the next step. Otherwise, abandon all hope.
-Copy the CC folder into a flash drive;
-Paste the folder into the vista computer, on the desktop;
-run CC.


This should solve your problem, since, from what you described, I'm guessing it originates from the installation procedure.