Thanks for your reply!
1. No, fan control was not on in BIOS. Now it is. Thanks.
2. I got the 30C right after I had taken off part of the case. It seems that the temparature dropped quite fast then. Another time when I looked it was 42C while surfing/installing software.
3. I am quite sure that the CPU fan is installed properly... I mean it is locked over the CPU and it is connected to the cpu fan connector. But, like I said, it feels like it still makes to much noise. I will double check if any cables are touching it...
I am going to install an 120 mm exhaust case fan in the upper rear and make it go slow, so I will at least have some air exhaust, just to be safe.
Thanks for the feedback! (And sorry for late response back from me)