Question about installing an old CS2 upgrade download

I had a hard disk crash.  I lost my old Photoshop CS2 and need it working.  I redownloaded from Adobe since I bought it online but it wants a previous copy available which I don't have an do not have my old disk as I lost it in a flood a few years ago.  What can I do?   I do have my old folder on my computer with Photoshop CS in it if that helps any.