How to install ASUS A8N-E chipsete fan

The chipset fan on my ASUS A8N-E suddenly started to make loud noise. I called ASUS and they have sent me a new fan which is slightly different. As far as I know, I will have to remove the Mobo from the case in order to remove the old fan. And the new one should just fit in with right orientation.

Has anyone done this and can suggest a few things to make this thing easier? I haven't done this before. I bought a combo so I didn't have to deal with installing heatsink/fan on CPU.

Should I clean the surface of the northbridge chip with anything before installing the new fan? If so, what should I use? The new fan already has thermal pad with sticker on it.

I would really appreciate if you can share your experience wity this stuff.