Computer Hardware are the various components of a computer. In the generic sense they are:
Case
Power Supply (PSU)
Motherboard
Central Processing Unit (CPU)
System Memory (RAM)
Storage (Hard Drives/Solid State Drives)
Graphic Cards (GPU)
The Case:
The case is the external shell of the computer. It's primary function is to protect the interior components, provide air flow direction for component cooling, and provide you with on/off capabilities.
The Power Supply:
This is what provides power to each component within your computer. This is the literal "Heart" of the computer. Just as a bad heart can lead to serious medical issues, a bad PSU can lead to serious computer issues.
The Motherboard:
Continuing with the human body analogy...