If it wasn't the fan blade or the heat sync it was likely vibration. If those ribbon cables are laying up against another piece of metal the small vibration from the running PC will overtime cause wear. Considering at a minimum that pc is on 9 hours a day, 5 days a week. That's roughly 70,000 hours in 3 years. If it's always on that 184,000 run hours in 3 years. You could cut through an Oak with a butter knife if given 184K hours. .