Well, I don't like very much playing the game in full screen mode, and I'm asking if there's anyway I could play it a window mode. I'm talking about Fallout 1, I forgot to write it on the title.

Sorry for my bad English.

i don't know if there is a better method but this is one way to do it, download http://koti.mbnet.fi/ton_hur/files/fallout/sfall1.7z and extract it to your fallout directory.

you have to edit ddraw.ini to alter the settings, on line 38 (Mode=0) replace 0 with either 1 or 5

1 is 8bit in windowed mode and 5 is directx9 also in windowed mode, the difference is that while 8bit version works well you can't change resolution and with dx9 you can edit the resolution (lines 48 and 49) but the movies are all messed up.

clearly not the best method but at the moment the only one i'm familiar with, maybe someone else has a better solution to this.

I've been reading the readme file and it says this solution only works for 1.2 version of Fallout, and I think GoG's version is 1.1. Also, it says you need the US version, and I think I have the EU version because I haven't seen any children ingame, not at least in Shady Sands.

Maybe I am wrong.

By the way, Is there anyway I can make a backup?

http://www.gog.com/en/forum/fallout_series/fallout_mods has links for the necessary patches to get children back and other nice fixes. gog-version should be 1.2 though so shouldn't be an issue even without the patches.

what would you like to backup exactly, if you are replacing certain files simply take backup from those, or if you are thinking about reinstalling the game or something, copy the savegame folder in data to somewhere safe.