You need to have fans in your system to cool down the electronic components. You can get rid of most of the noisy fans if you use a water-cooled system. But, you may still need a fan to cool down the water-cooling radiator.
You can reduce the RPM of the fans to reduce noise.
You have to weigh the trade-offs between what you want to use the system for, the temperature of the room it is in, the reliability you require, the noise you can tolerate.
You can remove all the fans. But, don't be surprised if you end up with a system that is very slow and freezes frequently to the point that it becomes useless!