Is this a timing belt problem? Alternator, battery, plugs and wires have been replaced. I don't know what to do

. Remove the oil filler cap, have a friend crank the engine, and verify that the camshaft rotates. If it doesn't the timing belt likely broke.

. Check all under hood and under dash fuses with a test light or multimeter.

. Check for codes.

. Check the ignition switch for wear, pitting, or melting. Remove the negative battery cable, prior to beginning inspection.

. Verify that there's plenty of fuel in the gas tank.

. Verify that the Check Engine Light comes on and goes out, when the ignition switch is turned to ON. Verify that you can also hear the fuel pump run, when the ignition switch is turned to ON.