usually after 1.  e4 - e5 2. Bc4,  Nf6 is played, and there is no Qh5, and Qc6 is pointless

and if: 1 e4 - e5 2 Qh5, then Nc6 is fine...

theres actaully a good tutorial on this, on the chessmaster grandmaster 11th edition by Josh Waiskin:)