ding the Defaults</h3>

<p>The default runtime framework may be overridden using command line arguments, 
   menu items in the Gui or settings in an NUnit project file. Provided that the 
   requested framework is available, it will be used. If it isn't available, 
   NUnit will issue an error message.
   
<p><b>Note:</b> To use version 1.x runtimes, you must have NUnit's support 
   for those runtimes installed, in addition to the runtime itself. This
   support is an option of the NUnit installation.

<h4