Use this dialog box to specify a launch condition that must be satisfied (evaluate to True) in order for the installation to launch. You reach this dialog box by clicking Add or Edit from the Launch Condition tab in the Project Properties dialog box.
Specify the launch condition here. If the Microsoft® Windows® installer determines at installation run time that the condition is true, product installation will proceed. If the installer determines at run time that the condition is false, product installation will terminate.
For a list and explanation of valid conditions, conditional statement syntax, and installer properties you can place conditions on, search in the MSDN™ Library under the topics, Platform SDK, Setup and Systems Management Services, Setup, and Windows Installer Programmer's Reference, for any of these terms:
One common launch condition often specified is:
VersionNT>=500
This condition stipulates that the product installation will not launch unless the installer determines that the target machine operating system is Microsoft® Windows® 2000 (formerly called Microsoft® Windows NT® 5.0) or later.
Specify the error message text your user will see if this condition is not met (evaluates to False) at installation run time and the installation terminates. For example, if the launch condition evaluated is a requirement for Windows 2000 or later, you could type this string to display if the installer finds a Windows 95/98 or Windows NT 4.0 operation system:
This software requires Windows 2000 or higher.