Purchased Creo 4.0 student premium after trying Creo 5.0 trial and it won't install?

Hi,

I've bought Creo 4.0 and when I go to install ... my options are all 5.0.3.0 or something and it all seems to be Creo version 5 programs. When I go to open the program, it says it's failed to obtain a license. I'm a bit upset and not sure what to do here. Why won't it install Creo version 4 programs? What can I do about this? I've just deleted everything including old licenses from past student versions and am trying again but it's still creo 5.0.3.0.