Reply to My S4 keep crackling.. what do..?

Hello, first of all, my english won't be perfect as im italian, second, thank you for reading and trying to help.

I've just bought and installed the traktor kontrol s4 and Traktor 2 and I have serious problems:

I've installed and connected everything how it has to be. When I play a song using the internal s4 audio device the problems start.. instead if I run Traktor with the internal audio device of my PC there are no problem. Guess what? To dj of course you need to use the s4 audio device so..

So now im using the s4 audio device.
I've connected my Yamaha hs80m that works amazing ( I've checked the yamaha and the cables that they worked and they work) into the main 1 and main 2. I play a track and here the problems begin: The audio begin to crackle. Even If i connect with only my headphones the problem is still there. Every 5-6 seconds it crackles, it jumps, you know what im saying.. And this only if im using the s4 audio device like i said.

Another problem is that Traktor the software crashes very often, especially when im chaning for example someting in the preferences. Then, when it has crashed, im not able to close the program, even if I use the task manager, I must turn off the pc and not torning off simply clicking the start and turn off. I must turn it off pressing the button for 5-6 seconds. Because if I restart the system normally and the s4 is still connected with the traktor 2 .. the pc won't turn off.

I bet it is not my pc actually, because before installing traktor I had just reformatted my pc. so it was clean like a baby.. My pc is:
HP Pavilion dv7 Notebook PC
Intel Core i7 , 2.30GHz
8 GB RAM
Windows 7

I've seen on the web that others have this problem, a lot because of the cpu, here I can say it is not the cpu actually because it never goes on the red..
I've also tried reinstall traktor but nothing.. I've tried change latency, turning wifi off,.. but the problem is still there.