if you are running windows 7, Just alt/tab out and back in again or control/enter. GL!

and here is something else that can help

https://www.reddit.com/r/ultrawidemasterrace/comments/538p1i/bioshock_remastered_ultrawide_guide/

You have to use the special options for your operating system and monitor setup. If you don't know what that is, no one can actually help you.

There is a section in the options menu that should actually help you, all bad jokes aside. You should give more info if you want better help though since we have no idea what resolution you're trying to achieve or what system you're playing on that may limit or inhibit your capabilities to do so.

sorry, i should have said it runs on win10 , any suggestions? thanks...........

this still works for 10... lol I used it for my 2 monitors

the link worked for me at the time of release on GOG. I am using 10 pro.

not quite sure how i did it but i have full screen now thanks.......

You should try going to graphics settings and scroll down until you see windowed mode and uncheck it

Sometimes app's like Borderless Gaming can be real helpful w/ these problems old games can have w/ staying fullscreen.

See this - https://github.com/Codeusa/Borderless-Gaming/releases

You two are answering a question someone asked 4 years ago, chances she/he's still looking for the answer are slim.