Google Maps does not show in windows XP

[routeconverter]

I am sure there is somewhere in the PC a file that stores the Routeconverter parameters because when I launch it, it keeps the memory of the last file I loaded. My thought is to delete this file and see what happens.

Have in look in the registry below [HKEY_CURRENT_USER\Software\JavaSoft\Prefs\slash\navigation]. I'm not aware of any registry setting that enables or disables the map but you might try to delete all the settings. Won't hurt.

Do you know how to reset the Windows firewall to zero ?

No. But the first result for http://www.google.de/search?q=reset+windows+firewall looks promising.