Karsten75 :
Ask your friend for some more help?
I read your post before the thread, and I was about to comment on how bad of a response that was to a thread, then I read the thread. Now I realize, that's a good response haha.
I'd like to know when it's freezing.. is it freezing during POST? Is it freezing a few minutes after you get into the Windows interface? When you try to log in? When you launch a certain program? When you get to the Windows loading screen? When you go to a certain website? Without more info, I will go ahead and address about two out of two hundred of the likely causes of the problem:
For a new build, it could be a bad install of Windows. Try to reinstall. It could also be bad RAM, it could be bad CPU, it could be bad GPU. Could be a bad hard drive also. Download Core Temp and MSI Afterburner (links in description). Generally speaking if the temps are above 50 after you download Core Temp, there's probably a problem (assuming that the program is all you're running). Afterburner shouldn't be reporting higher than maybe 60 when you open it. Other possibilities can be explored with more information regarding the issue. Try what I said and tell me what the temps say.
Core Temp: http://www.alcpu.com/CoreTemp/
Afterburner:
http://event.msi.com/vga/afterburner/download.htm
Please respond with the temperatures you see.
Edit: For future reference, you will learn that it really annoys computer techs when you say something such as "my computer is slow help me fix it" or "my computer is freezing what's wrong?" We need to know when it's freezing and other things that can help us, not just the symptom. The symptom of freezing can be caused by literally thousands if not tens of thousands of things.