We’ve explained your issues numerous times and you even show a screenshot of the problem in post #3 which gives a big clue as to what is wrong.
You have designed a site that fits only one monitor size and it is likely that you are the only person seeing it that way. Nearly everyone else gets the broken version.
You have to design in a way that suits all screen sizes which is why you cannot keep throwing magic number solutions at your problems or using methods that don’t adapt to different screen sizes very easily.
A responsive design is one that adapts to the screen width available appropriately and is usually achieved by creating fluid designs and then media queries to re-arrange content for smaller screens.
At the moment your site only works if you have your window open at around 1450px so as a start I would suggest that you limit the max-width of the page to 1450px for now until you work your way through the other issues. You can limit the max-width of the page by placing a wrapper around all your content and setting a max-width of around 1450px and using margin:auto to centre it. You could use the body element but generally that causes more issues than it solves spo you would be better using a page wrapper div instead.
(The second rule is to put yoor fixed footer on top of the page content as you have elements covering the footer as they scroll).
If you want to test quickly the centering effect without adding the page wrapper then you can add that rule to the body instead just to test.
With that rule in place your page will look like this on all screens from 1450px and above.
The task now would be to make the page look better from 1450px and smaller as the layout overlaps badly at 1250px approx. That will be no easy task and will not be solved by a quick search at SO. It will require a sustained effort with meticulous care and working through the page one element at a time in order to make things fluid and responsive and mostly automatic. i.e. limited positioning and avoiding fixed heights and width wherever possible.