Ok, your abs light is 99% one of the sensors is gone, read the model and type of your abs module, some of them have built-in diagnosis , no need for connecting computer , you just need to connect some pins in the diagnostic connector to the ground and then count number of flashes of abs light and it will give you the code of the error. I will try to find some more info on this and let you know.
Regarding the engine diagnostics, what i found that works best with italian cars of that era is program called VISA uniscan
, but it requires DOS based computer to run (I used desktop PC from 2000 and COM ports (not USB) it is prehistoric in today`s standards but it gets the job done. Do some research on this forum there are tons of very useful tips here and you can learn a lot
Regarding your window issue, oh it is out already..what to do, you will find the joys of setting the window back again
just joking around a bit couldn`t help it sorry. The plastic part inside the `rail` is fixed on one side and movable on another. Do not try to make loose the fixed side! But as you say if the other one is broken I assume it could be easily fixed with a screw or something like that. Try to repair the mechanism as finding another is a real headache it took me 3 months to rectify similar issue on my car!
P.S. just saw the images of your car
it look amazing, here in Montenegro we do not have so well preserved example. Good luck with it