Reseed and ariate in the fall around Sept 1st. Put down plenty of lime. In the spring put preemeregence for crab grass and spray for broad leaf weeds. You might need to spray twice but before its 80deg out. This process might take two years to get the weeds out. Make sure you do this every year. Keep the leaves off the grass in the fall. You can take a yard with no grass and in 2 years have a great lawn.