Open a command prompt, type the following:

perl -le "print $^X"
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Copy the output from above (e.g. the output for me was D:\perl\bin\perl.exe), run the following from the command prompt (remember to change my example path for the output of the first command):

assoc .pl=PerlScript
ftype PerlScript=D:\perl\bin\perl.exe "%1" %*
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test.pl will now run the script rather than open it in your text editor.