October 2016
This thread maybe helps you http://answers.ea.com/t5/Origin/Theme-Hospital-screen-size-help-needed/td-p/4257051
October 2016
F11?
December 2019
December 2020 - last edited December 2020
Old question I know but for those in 2020 still wanting to play this try right clicking on theme hospitals desktop icon go to Properties then Comparability you will then see a box saying "run in 640x480 screen resolution" tick that and it should now work.
(Yes it's not 1080 but at least it's full screen)
December 2020
Hey @DarK-MnKeY1 thanks for sharing the fix that worked for you.
I am going to lock this thread as it is quite old.
Darko