My car won’t start I just bought a brand new battery and new alternator , could it be my spark plugs?

 

welcome to the forum. Due to the lack of vehicle info will take a guess i take it that the starter turns the engine and no start, timing belt broken or skipped a tooth if over 110 miles since last belt change. fuel pump failure if ran out of fuel and left the ignition on for a while or tried to start it without fuel, ignintion switch at the key failure, (4 spark plugs do not normally fail at one time nor does the ignition coils fail all at once)

 

Question: Is this a crank, no start? Or, is this a no crank, no start?
Each one deals with different parts of the car.
No crank, no start ... it deals with the ignition/starter circuit
Crank, no start ... it deals with what makes the engine run
You can always come back here and ask questions or give more information
If you have time then you can also look up your issue on youtube.
It will help you understand what we say about the situation