Just hit CTRL+SHIFT+ESC to bring up the Task Manager, Under the Processes Tab, look for VoiceAttack.exe*32 click on it, and hit the End Process button. That should close VA, then all you have to do is start it again, then you should have access to the settings, and you can change what needs to be changed.
If that doesn't do it, you might have to uninstall, and reinstall VA.