When I double click on a Prism script file (.PZC) notepad opens. I want Prism to run that script.

Earlier versions of Prism (prior to 5.02) registered the PZC extension so it is opened by Notepad, for editing. But you can tell Windows to instead open Prism, and ask Prism to run that script. Follow these steps, which are the same for Prism 4 or 5, and  for Windows XP and Vista.

1. Go to Control Panel -> Folder Options -> File Type ->
2. Choose PZC in the list.
3. Click the Advanced button.
4. Select open action in the list, click Edit, click Browse and choose Prism.
5. Add "@%1" to the path to Prism, so that the strings looks as follows:
                   "C:\Prism 5.01\prism.exe" @%