i keep seeing posts that 1.13 latest patch works on windows 7..well i use windows 7 32bits and well the screen goes dark and it stays this way.
i did try to run as administrator and with WIndows XP SP2 and SP3 compatibility....i installed it in a gog.com folder...not a program files one...and vanilla JA2 worked fine.
I don't know what else to do...anyone got any ideas ?

I can verify that JA2 1.13 works with windows 7, since that's the only platform I've used for it.
Now, on to further questions.
Which version of 1.13 did you install? It is possible that you've installed an outdated one, or just the hotfix instead of the full release. I would suggest grabbing this one which is the (currently) latest version. Even though it says unstable, that is because it's compiled from the latest source code, and bugs are always a possibility.
Second question. Does it show a black screen both on full screen and on windowed mode? You can try changing this in ja2.ini [SCREEN_MODE_WINDOWED = 1] though you will have to set your desktop's color depth to 16-bit instead of 32-bit.
Third: It is possible that the black screen is just the inability to play the intro videos. Again, on ja2.ini find the line [PLAY_INTRO = 0] and see if this helps.
Other than that, no idea unfortunately.

i have the last stable version and the uppdate on 1 july...so i think i have the last one...windowed mode ?yeah..i tried selecting that..it still goes to full screen for some reason..will try to enter without intro movies...

well no use...i disaled intro movie and it still won't work...maybe 1.13 last version is bugged ?cause vanilla game works fine

4552 is working fine, since a lot of people are using it without problems. The inability to change between windowed/full-screen mode even after you modify ja2.ini seems to indicate a problem with your installation. So, one last try before I raise my hands in the air admitting defeat.
1) Go to www.mediafire.com/tais113stuff and download one of the 3 Single Click Installers (SCI). First one is the AIMNAS, second is the Unstable 1.13 and third is the Urban Chaos one (which is in 2 parts).
2) Do a fresh install of JA2.
3) Extract the SCI on a temporary folder and then copy it on your JA2 installation directory, overwriting.
You should end up with a folder that contains at least Data and Data-1.13 folders, and maybe Data-AIM or Data-UC depending on SCI used.
If it still doesn't work, then I've no idea at all.

P.S. In case you are using 2 graphic cards, try disabling one of them or setting the game to SingleGPUMode (or however it's called). I recall JA2 having issues with crossfire, but it was mostly graphics not updating.

I just have to respond to this comment. Not trying to go off-topic.

I install everything to the "Program filesx86" area. Games, programs, you name it, they all go there. Every game I bought here on this site goes there, and they all work without a problem installing there. Jagged Alliance 2 works there, etc.

If you have specific problems with the folder, then say what they are, maybe you can find a way to fix it, because installing there does not stop games from working.

I am guessing you are younger or simply do not play the number of games I play. At every forum I visited about PC gaming the most common reply I see from those who know in regards to games not working right when installed in Win 7 is "Do NOT install in the Program Files(x86) area!". I was having many issues myself with many games and re-installing them to a different area solved the issues. YOU may have gotten whatever games YOU play to work this way(installing them to the default Program Files(x86)) but that does not make this a good idea or even generally applicable.

Win 7 has security features that hamper installation to and running from the Program Files x86 folder(one reason why viruses/malware are not common to Win 7 the way they are with other Windows versions). Many newer games are programmed with this in mind and thus work fine but many(most?) older games...not so much.