If you are packaging the Flash player install (already downloaded) with your disk or drive, all you need to do is check to see if they already have it installed, and then launch the program from your installer if they do not.
I assume you expect and know how to check for current installation, minimum version requirement, etc.--before and after installation to detect and verify correct results.
As an alternative to including the Flash player with your install, consider checking for the currently installed version against your system requirements within your application and give them an install dialog (or MessageBox) to launch and get the latest Flash version.
that is too complex what i need is for the installer to detect the current version on the computer then if its not the current then update it else dont install at all. I was thinking of a condition statement but i dont know the syntax