I am helping a business in today that had a message come up on their saying fan error. After taking apart the case and having a good look inside I was able to see that the CPU fan was so filled up with dust that it was unable to spin at all. After disassembling the fan and giving it a good clean everything was good to go.

 
Mark JANSEN | DIGITAL INSITE 
Computers + On-site Support
Mobile : 0404 110 526 |  digitalinsite.net
398 4 - Lonsdale onsite computer repairs and support