90B Error on HP Laptop

[Optimus_Prime]

I'm getting following error.
Do i Need to change the fan or just cleaning the vent will solve the problem.
My laptop is still in 18 month extended warrenty if I have to change the fan Do I need to pay anything?

 

[Optimus_Prime]

last time I changed the fan as it was in warranty. and again getting this error after almost one and half year but now I am out of warranty.