27" CinemaDisplay with (non Bootcamp) Windows 7
It's hard to tell what is your problem connected with, I'd rather try connecting another monitor to the videocard you have so that it could be possible to check whether your DisplayPort is working or not?

As to the bootcamp install on Windows the following worked well for me:

in the folder BootCamp\Drivers\Apple BootCamp.msi is located.
Try launching it with Admin privileges using context menu