90 mustang 5.0 won't start.....

Just bought the car after it had sat for aprox. 5 years, ran it for a couple days with no problems. then it started sputering and backfiring so i dropped the gas tank put in new fuel along with seafoam, also replaced spark plugs air filter fuel filter and fliuds also redid the timing, first it just kept buring spark plugs now i cant even get it to turn over what could the problem be???

Welcome to the forum 90mustang5.0. It sounds like you burned up the starter by spinning the engine over too long while trying to start it. What do you mean by "first it just kept buring spark plugs"? I'd check to fuel filter again to see if has plugged up with rust and crud that might have been in the gas tank.