All parts of computer are controlled by?

The computer isn't controlled by any one part it is a system on many parts working together but a more helpful answer might be you, you tell the computer what to do therefor, you control the computer

Hello friend! I'm OP, a Hardware & Networking Engineer, I want to tell you that it is Operating System that control the whole computer system. It is the first thing which get installed into your computer system and during installation it check the whole configuration of your computer system so that it can prepare ourself to handle the system. All other software works under this software.