The Adobe cs2 suite is now free. Not sure if it has a Dreamweaver in it or not.
Just Google free Photoshop cs2 and it should give you a lot of links to download it from. Adobe also furnishes the SN and it's usually on the download page on the site you download it from.
I just found this explaining and also how to get DW cs2 from Adobe and not a download site. We already have cs2. I know several people that downloaded the cs2 suite without any problems from a download site other than adobe and works just fine. They told me Illustrator cs2 acted a little funky on Windows 7 but runs fine on XP. Photoshop and Imageready work just fine on 7. I have both plus Indesign cs2 on 7.