Question about CPU fans – Computer Science Stack Exchange

I recently bought a computer with an As 970 rock motherboard and decided to change the processor. I looked at the fan and found that it had a lever with 2 latches. After locking it, I tried to remove the processor fan. but that seemed to be stuck and so I looked for another way to attach other than the latches. I did not find anything that looks like his outfit in place. Does anybody know why? It's been said that the old processor's paste could act as glue and that all I have to do is give it a little twist, but I'm afraid something is not breaks if I do that.