To perform a silent uninstall using the msiexec command:
At the command prompt, type an msiexec uninstall command in this form: msiexec /x <product.msi | {product GUID}> /qn
Use the name of the Crystal Ball msi, in place of product.msi or use the product GUID for the installed version of Crystal Ball. For more information on msiexec, visit http://www.microsoft.com or type msiexec ? at the command prompt.
For more information about the Crystal Ball msi, see Installing and Licensing Crystal Ball with a Script.