Windows Wifi - WPA2 vs WPA2-PSK option grayed out? what's the difference?

ok i'm trying to set up my wifi and when i go to the windows wifi options and set up my network, when i choose "WPA2", the options to enter the network key is grayed out. But when i choose WPA2-PSK, i am able to enter the network key and it's not grayed out.

MY question is what's the difference between the 2? why are there two wpa2 options? I know PSK stands for preshared key but I mean when you choose an encryption, you're forced to put a network key, So that means when i choose WPA2, you should allow me to enter the key, not gray it out. WHAts' the point of having 2 WPA options, that's redundant and have one grayed out while the other is not?

Please check my pictures below

 

In this case WPA probably stands for WPA- Enterprise with RADIUS server.
In such a case there is no network key as such but a RADIUS server IP and password should be supplied - which is why network key is grayed out.
Where should it be configured, I can't tell since I'm not using the same version of Windows and my settings look different, but probably in an "authentication" tab.

 

If you go to the Authentication tab, you will have everything grayed out when using WPA2-PSK. WPA2 is WPA2-Enterprise. They name it WPA2-Enterprise in newer Windows version.

The University that I went to had WPA2-Enterprise. We had to download a certificate and then authenticate with our University's email account. It had advantages for the University such as: Disable access for students when they leave, Prevent free access to the network if they know the shared key (which would probably be leaked online), Limit number of connections per account, Know who is hacking/doing illegal stuff in their network, ....