Why wont car start after tune up 2004 Chevy Malibu just put new spark plugs one

Hello, If the engine was running with the worn out plug, but not running with new plugs, there is an error in installation. Either the plug is the wrong type for the engine, the coil pack is bad, or there is a lack of continuity between the coil and plug, or coil and wiring harness. Also, the spark plug may not be seated in the head (but don't crank it down), or you may have a bad fuse due to servicing without removing the negative battery cable.