Set up and Deployment issue using vb.net?

I am able to create and install the package successfully using vb.net.
But, there is one issue while setting the Default Location to D drive.

I have changed the properities of Application Foloder as

Default Location : D:\[Product Name].

The package successfully installed at drive D. But, the issue is
If the drive D is not available in the machine then it has to
install at drive C.

Current it is throwing an error message "Drive D: is not available".

I don't know how to put that condition in the Application Folder properties.


Chandra Sekhar V