if you have "registered" adobe when you originally bought it then they should have a record of you owning it and direct/send you a replacement copy. ( interpreted: if you haven't like so many of us trying to avoid the ocean of spam they will send indefinetly you will need to find someone near you and "borrow/burn" their copy so you don't run into this problem again. )

jim

p.s ~ CS4 is just amazing , I love it!