I don't see why you want to use perl for this when you have "regedt32" (or something that looks like that ... it's been a while). See for example this article on the issue. I don't have any Windows machine over here, so I can't test anything, but do remember that a ".reg" file is easilly created and executed.

Besides that, you must have a policy/solution for updating your clients already, for I don't believe you run around updating 3000 PC manually. I bet there's a tool you use already to edit certain registry keys. Just hack these edits in there :)

Update: Ermm, please excuse my ignorance for believing MS would store such parameters in the infamous registry. It seems like you need to hack the desktop,ini file in each directoryfolder, which, of course could be done with Perl. Or just copy a "right" desktop.ini to all the "folders" on your clients that need updating (which is probably faster and doesn't require Perl on all the 3000 machines)