how do i replace a heatsink and fan in a Fujitsu amilo li2727?

The laptop has been overheating and powering off but fan is very difficult to access .i tried hoovering the back fan vent and a lot of dust / cat hair came out .
I tried powering back on and it still powers off so I take it the fan is faulty ? If so how do I remove and replace ..as the back service plate only acesses the heatsink and not the fan ..