Ranxaeroth

Followed the instructions to run the mod pack. I click "play" and it goes to the mojang screen and .....nothing. I let it run one time for over an hour....nothing. No errors...nada. Out of over 20 times of attempting to play, only got to the "create new world" screen 2 times. As soon as I clicked the button.....forever pause. The only thing Im getting for an error is......"not responding" I have a brand new, fully updated HP Envy H8 , AMD 6 core FX-6120, 10GB DDR3, with an AMD Radeon HD 7450 graphics card. Any thoughts?? I can run Hexxit maxed out and several other modpacks just fine.....just not yours. It looks amazing so I really would like to get into it, but cant start it up Any thoughts on how to fix would be great.