Hi my double sink won't drain, I've ran the snake through all the piping, as far as I can. I've plunged it put draino down, tried hot boiling water nothing seems to be working. I was at a point where the water would drain but now when it fills up the plunger won't even work. I've tried all I can think of. Is it possible for it to be a vent problem?

No, snake the line again. How far did you snake before? What kind of snake did you use?