if ( exists $bad_stuff{$subkey} ) {
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Careful. That line would only match if the target machine's registry contained the exact string that I used to key the $bad_stuff hash. I used the hash so that I use a regular expression match to increase flexibility in what the code would catch.

E.g.: If the registry contained "LimeWireInstallDate" (Made up example), your version wouldn't catch it. I also assumed that it would be possible that software would install registry keys unrelated to the software name (it could use the software vendor's name instead, for example).

The point about SV_TYPE_ is a good one though, thanks.