Solution
To launch an external application, you can use the LaunchExecutableEx function. This function runs a program and returns without waiting for the program to exit. There is an example that ships with LabWindows™/CVI™ where you can check how to use the function mentioned before. The example can be found in Help >> Find Examples... >> Communicating with External Applications >> Operating Systems >> launchexe.cws.
Another option is using the ShellExecuteEx() function available in the Windows SDK.