The instructions on the [http://www.activestate.com/Products/activeperl/ ActivePerl] site are pretty detailed but you need to remember to do the following or nothing will work quite as you planned…
Then, from the desktop…
select Start
Right click on 'My Computer'
select the 'Advanced' tab
click 'Environment Variables'
find the Path variable in the lower list
click 'Edit' then copy the contents
click the 'New' button under the upper pane and add the variable 'Path' with the contents as copied.