How do I remove the Delta black label from HSF?

[Citadel535]

I put a custom thermosonic thermoengine with a delta black label fan. I am kind of fed up with the noise of it and want to remove but the screws wont come off from the heatsink to the fan. I want to put the original thermoengine fan on it but cant figure out how!

Please help!
--
Citadel

 

[Swanny]

Either unscrew the screws or unclip the clips. I don't know the design of that HS, but it should be pretty easy to find what is holding the fan on.

 

[Citadel535]

The screws won't budge for some reason. It looks like each of them are in some kind of spring to hold them. Don't know what to do.