When I choose any topics from Prism 5 Mac Help, the help window opens but is blank.

First, repair disk permissions:

1. Run the Disk Utility located at: [system > disk]:Applications:Utilities:Disk Utility
2. Once inside the Disk Utility window, select the System disk
3. Go to the First Aid tab and then click the Repair Disk Permissions button. Be sure to choose your hard drive, not the program CD or DMG 'drive'.

If that doesn't solve the problem, please reinstall Prism.