I guess you can still dl the latest build from
http://www.prodesktop.net/ the problem is the activation code as you heard. There is one way though. If you have activation codes AND the corresponding 'hd volume' or 'logical hd volume' number you can reinstall it, just set the volume ID to what it was when ProD worked and activate the instalation. You can check volumeID tag like this
D:\>vol
Volume in drive D has no label.
Volume Serial Number is XXXX-XXXX
or
D:\>vol c:
In the
http://www.prodesktop.net/ forums it is one of the topics, just search the board.
Just before reinstalling my Win2000 I upgraded to 5 year licence and have my volID and working serial. Worked for me.
Konstantin