The game doesn't fit my screen anymore

hello,

I have a problem with the display of the game, i explain:*
(i play on a 15.6'' laptop , my screen resolution is set to 1366x768)

i use 800*600 res in game.
before this problem, when i was starting crossfire the login screen would positon itself at the center of the screen, after logging-in, the window game fit my entire screen with the black bars on both sides, and same thing when i enter a map , nothing but the game display and the black bars would appear.

but for a reason i ignore, things go on this way now:

when i start to login , the window is not centered like before

https://s26.postimg.org/kwxvia1g9/login.png

And when i enter in the game it's not centered too and blackbars won't appear:

https://s26.postimg.org/pckw1a389/gamemenu.png


And finally when i enter a room i end up with this


https://s26.postimg.org/jpoj3t0pl/ingame.png

i tried to change my resolution on crossfire, changes nothing. If i change my native resolution to 1024*768 i have the same display like "in the past" but ONLY in game menu, not when i'm in a match, which is what i want...

i also tried to delete all the .dat files in the documents repertory but it doesn't change neither.

I looked a little over the login ui parameters but i can't find a way to center it and something tells me that it probably won't change anything to the problem when i'm in a match.

thanks for help