Originally Posted by Erda
You need to call the number on the bottom of the second linked page to order Windows 7 Professional.
No, you just have to click the link by where it says "Need to join you school's network domain? Click here."
See this post
Then you can add it to your cart just like Home Premium. No phone call necessary.
EDIT: I see now you're talking about the direct link to the Microsoft Store, not the Win741 site (which is also run by MS). Not sure why anyone would do that, though.