I’ve had some noisy and stuck 120mm computer fans in both my desktop and my server. I initially planned on replacing them but realized that all they really needed was some oil. The process is pretty simple and well outlined by TechRepublic. I removed the label and the small plug, put a drop of (sewing) machine oil on the shaft, gave it a spin, and reassembed. It’s nice to have some quiet in the home office again.