Ja jak włączyłem 1280x1024

Jak odpalić grę w tej rozdzielczości?

BF42 doesn't officially support higher resolutions like 1280x1024. There
is a way to force it though.

First go to:
C:\Program Files\EA GAMES\Battlefield 1942\Mods\bf1942\
Settings\videodefault.con

Change the line:
renderer.allowAllRefreshRates 0

To this:
renderer.allowAllRefreshRates 1

Then go to:
C:\Program Files\EA GAMES\Battlefield 1942\Mods\bf1942\Settings

Edit the following files:
video.con
videocustom.con

every time you see:
game.setDisplayMode 1024 768 32 85

edit it to whatever you like in this format:
game.setDisplayMode x=res, y=res, colordepth, refreshrate

e.g. game.setDisplayMode 1280 1024 32 75

Then set both files to read-only,
(if you don't want the settings getting changed).

If you are still using the default profile, instead of custom, then go to:
C:\Program Files\EA GAMES\Battlefield 1942\Mods\bf1942
\Settings\Profiles\Default