Jo,
assuming *doze, before you install Perl, backup your registry, install perl, and backup your registry again (to a diffrerent file) to see what modifications it has made, then you should be able to delete these keys, and executables that remain will be overwritten with new ones when the new install starts, or you could build a standard unpack list
HTH, or at least gives you a start
--Paul
It's important in life to always strike a happy medium, so if you see someone with a crystal ball, and a smile on their face ... smack the fecker