InstallAware

I need to get the full path to where the product is installed.

For example we have done a full installed with version one choosen the targetdirectory and installed the product.

Next time when I run the setup I need to check where there product is installed inside a if statement (needsupgrade).
I need this to copy a file from its installed destinationen, but I don't know where the product is installed second time.

Thanks

Martin