Deleting a system dashboard will remove it from the list of available system dashboards for all of the Dynamics CRM users in a system. In order to delete a system dashboard, the user will need the System Customizer or System Administrator security roles.
Deleting a System dashboard requires you to navigate to the Customization section in the Dynamics CRM 2011 Settings area.
Carry out the following steps in order to complete this recipe:
From the Customization section, click on the Customize the System link, as shown in the following screenshot:
This will launch the solution editor dialog showing the Default Solution for Dynamics CRM 2011. Click on the Dashboards link located in the left-hand navigation section.
A listing of the current system dashboards will be shown. Select a system dashboard and click on the Delete button in the toolbar. I suggest you create a test system dashboard to play with, rather than deleting a system dashboard...