Hi,
I dunno what kind of clip you fan has...
I'm using a GlobalWin FOP38
http://www.overclockers.co.uk/acatalog/Online_Catalogue_CPU_Coolers_2.html
This was a biatch to install, but I finally cracked it (not the core tho, luckily!)
I seated the fan squarely over the cpu, hooking the locating eye under the proper place on the socket, I then pressed the springy bar (not the flappy bit at the end of it) down with a pen (guided by hand incase of slippage) until it was compressed enough to fit under it's retaining clip (fair amount of pressure required). I was particularly careful not to press down too fast with the pen (and also when compressing the same clip to remove the heatsink) as this is when it can damage the tracks on the mobo.
The "flappy bit at the end" kept pinging off (grr) when I pressed it down with my fingers, which is why the pen on the springy bar idea came to me.
All I need now is a digital so I can take some pix :O( Hard to describe in text methinks
HTH
<font color=blue>Moots</font color=blue>