How to take off the fan on motherboard

Why do you need to remove the fan?

If you're looking at it from the bottom is there a little pushpin in the center of the studs holding it down? If so then you need to push in the center of the pin and gently pull it out from the top while also squeezing the parts together on the bottom. The other favorite method for securing them is the popouts. Again, from the bottom of the board if you look real closely at the studs where it comes through the board you can see that it's split and has little catches holding it in place. If you squeeze them together while gently pulling them out from the other side they should come out with a little difficulty.

Thank you very much!

I will try it exactly the way you said. Looking very very close is a very good idea, I didn't think of this earlier.

Thank you again!