Thanks to all for the help ... I checked out settings->control panel->folder options->file types and there was clearly some sort of problem. The Perl icon showed a wrong description and the buttons were greyed out, so I created a new one as per the faq link from simonflk. Now, when I do perl -e "print qq(@ARGV)" Foo bar baz I get Foo bar baz, but the original problem remains -- my scripts that use @ARGV are broken, but the ones that don't still work fine. If the problem was just with the file association, then am I right in thinking that *all* my scripts would have been broken, not just the ones using @ARGV? Any further advice much appreciated!