Question
Hello!  Hope you can help. I'll give it a shot ... in a nutshell ... 1st, I raked out all the dead / brown grass in many random areas in the front lawn, put down about 6 bags of Scott's Turfbuilder Plus, raked and tilled all the areas, threw down a ton of grass seed, put down a bail of hay, watered it a few times a week in the early morning ... however, nothing grew. Nothing at all.  I ended up finding out my fiance put down Weed N' Feed on the entire lawn the day after I laid and spread all the topsoil and seed. Well, that killed all the potential new grass etc.  HOW LONG DO I NEED TO WAIT UNTIL I CAN PUT DOWN MORE TOPSOIL / MUSHROOM COMPOST AND RE-SEED all the problem areas and do it all again?  This all happened 2 weeks ago.  Thanks so much, Mike

Answer
Between the 'W&F' and the Turf-builder Plus ?you have ensured that very little will germinate and grow for the next three weeks, at least! I am going to assume that the six bags of Turf-builder Plus ?was put down on the square footage specified on the label.
The best suggestion I can offer is to watch for anything to grow from seed before you put down a small quantity of grass seed, water well and regularly  to ensure maximum germination.
When you are satisfied that enough (80%) has germinated, then you can go ahead and sow the entire area.