Desktop and Laptop fans have to be cleaned out once every year
Proper airflow within the chassis is critical to maintain optimal operating temperature. Dust can build up in various fans (case/power supply/CPU) causing them to slow down or seize up all together. The excess heat can cause the CPU automatically to throttle down its speed to avoid overheating. Eventually components might fail altogether.
Laptops are more sensitive than Desktops
They have less airflow and components run at a higher temperature. Dust can cause heat related problems including premature component failure.
You can purchase a 1 hour Service Voucher from here. You can use this voucher on you next repair or service.
You can also purchase a minimum 1 hour Service Voucher if you need remote access repairs carried out on your computer - to learn about remote access click here.
Dirty CPU fan