Splash Title and Purchased Game Do Not Match

I bought the original GW when it first came out. I stopped playing it several months ago and uninstalled it. Recently I reinstalled it and have started playing again. Here's my question:

At the Login screen, it says "Guild Wars Nightfall" at the top of the page. When I go into edit account/manage access keys, it says I'm authorized to play Guild Wars Prophecies. Why does the title page differ from what I bought and am authorized to play?

There are now two more Guild Wars games; Factions and Nightfall. With Nightfall being the newest addition, that is why there is a new title screen.

Also, there was a new title screen when Factions was released

Oh, ok. Makes sense now...thanks.

yeah, this gets a lot of people, basically all the games are just chapters of the same game... Now you have it installed, i could come round to your house and load up my characters on your computer as nothing is saved on your computer apart from Screenshots and build/equipment templates