how come in the second bar of ``clair de lune`` by debussy where it has the two notes G natural and A flat playing together, it sounds horrible and wrong when i play it????? does this happen when you play it or am i just reading it wrong? and does it sound wrong for you?

Hmm - I think, you are reading it wrong... In my version it`s an a and g-flat, and there`re no problems here! I suppose you should just try and look at the notes again!
Regards...

In mine it has a G-flat and an A-natural.

yes now it sounds right. thank you. it was just a misprint in the music.