A person can find very solid, and informative advice on Internet forums. Then again, I also see advice such as post #4, which is completely misleading, and inaccurate, no matter how well intended.
There are some excellent HSF with top mounted fans. That is no criteria for determining quality. A vertically mounted fan is no guarantee that it is of high quality, or that it needs thermal paste.
Now Jasy19, you can follow the advice in post 4, or we can continue with a proper methodical approach to correcting your problem. Which will it be, because you can't do both.
If you'd like to continue, and you have no idea what HSF you have, just take a couple of good clear photos, so I can see what it is, and how it's mounted.
Here's a video that shows the stock FX 8120 HSF...see if this one is yours, or Google yourself some photos to verify.
Bulldozer Build: AMD FX-8120 Bulldozer 8 core - YouTube