Yes, it would be good to know your location and what type of grass you prefer to grow.
You could sit down and get comfortable and dig up every weed in the entire lawn. It takes a while but it does not involve using chemicals. After the weeds are gone you can re-seed the lawn.
You could kill the old lawn including the weeds by using a Round Up type product for lawn grasses and weeds. Wait until everything is completely dead, remove all the old vegetation.
Or you could rent a sod-cutting machine and cut away the old lawn and weeds.
Before planting the new lawn it would be good to incorporate organic matter into the existing soil; a rototiller will make this job easier. Once the soil is prepared you have the choice of using seed or sod.
