QUOTE
DFI LPNF4-SLI-DR
sounds familiar, Seems to be the motherboard in the next room that didnt' even work out of the package for me..haha.. Love those motherboards for being so poorly designed...
Im assuming I haven't gone stupid and you're meaning your CPU fan that gets attahced to it to to prevent your CPU chip from overheating like hell
in that case its just simply figuring out how to detach your fan from its slot, Depending on the processor it might be attached to your cpu because of the compound you put on it or that got put on it, that part will be really tricky to do if that's the case, Im not 100% sure how to do that exactly..
Assuming your fan is much like mine, Which is a long shot, There should be a screw on one side of it that you can losen, I actually had to walk to the next room to get the look at the DFI, basically the board has a hook design for cpu fans, which basically requires one side to latch on the bottom area of it, If not both, so if you can loosen the one side of the fan enough to unlatch it, the other should come off no problem
if your cpu is attached to the fan via the compound like I said, I have no idea how to go about that,
This might confuse you more than help you but, Eh, Hope it helps a little

EDIT:
Here is a quick picture of your motherboard bare, To better illustrate what I mean...
if you look at the yellow square in the middle you'll see 2 fork type areas, Your CPU fan should latch onto those, and there should be some way of loosening the grip on it, Most likely a screw like I said, So just loosen the one side and it'll unlatch