I believe the OP had hardcoded some values in the comboboxes. And that's why the code is not working.

And to get the path to Desktop or MyDocuments(which is different in XP and Vista/Win7), you could use the My.Computer.FileSystem.SpecialDirectories. For My Documents folder, it would be:
Code:
Dim strDocu as String = My.Computer.FileSystem.SpecialDirectories.MyDocuments