Compaq Evo N610c - how to open and clean fan from dust.

Hi.

I have HP Compaq Evo N610c. Laptop was never clened from dust (Im a second owner). Last summer i was force to byu colling pad because i was affraid overheating - HDD temp war higher than 64C (147.2F). Without coolling pad temperature of hard drive is somwhere between 54 and MORE Celsius ( 147.2F). I think fan collect a lot of dust from this years and should be cleaned. But - how to open this laptop and clean the fan safely? I don't have experience with something like that. Without cooling pad laptop was be overheating long time ago.



ps: sorry - english is not my native language.