Recently i installed Morrowind again, but this time i had in plan to mod it, so anyways many mods later, i started the game and it was going smoothly until suddenly my jump button stopped working, so i am asking you if you can help me fix this problem.

I tried starting a new game but it wouldn work.

The easiest way for checking the cause to this problem is to try rebinding Jump key, for example try using F key instead of standard Space key. If it works, it means you got a keyboard problem, if not, well, then I don't know what to say. Maybe check Morrowind.ini bindings.