You can't, as I've just discovered. Adobe will not provide a download or replacement disc for "a product so old." You can give them another $1k+ for the newest version of course. Really inspires brand loyalty and consumer confidence, doesn't it?
Wow, that really opens up a whole new chapter for me on staying with Adobe. I paid thousands for my CS3 and I'll be damned if I will show product loyalty to Adobe if they are going to be so ******!
Please go through the given link: http://prodesigntools.com/download-adobe-cs4-and-cs3-free-trials-here.html and download CS3.
Kindly follow the very important instructions before download.