I have a mid to late 2008 Macbook. Most of my use is online with Youtube and other video sites. In the last year to two years I've noticed that the fan will turn on pretty quickly after I start using the machine and will run at almost max rpms and then it will very rarely shut off. It just keeps running. Does anyone know if there is anything I can do? I thought maybe there is some malware installed thats running and that's why the fan is on, but I don't think reinstalling the OS will help? Any thoughts on how to fix this?