Cactus Music
But if your trying to install it on a Windows 7 or 8 computer I doubt if it will work. 

There are some users successfully running Sonar 6PE on Windows 7 who post here occasionally.

I'm making an assumption, but it sounds like the confusion here is that you are trying to register serial numbers that are already registered. If you already have the serial numbers and registration codes, you do not need to fill out our registration form again. Trying to do so will tell you that you can't.
 
All you need to do is enter the serial number and registration code into the software when prompted. I hope that makes sense! If you get stumped give our Customer Service team a call. Contact info is here: http://www.cakewalk.com/Support/contact/default.aspx