Usually, the hard drive connects to the motherboard.
Motherboard
All of them would be classified under "hardware" although the other devices connected to the computer would be classified in the subcategory "peripherals".
CD/DVD Drive or Card Reader.
computer case
A CD/DVD Rom drive is connected by either connecting an IDE or SATA data and power cable to the drive, the other end of the data cable is connected the a slot on the motherboard and the power cable already comes out of the PSU.
Because, it holds the computers, hard drive, fan, disc drive, ram, other key components, that laptops don't have.
series connected
An external hard drive is a device similar to your computer's hard drive. The difference is that it is portable. You can save files on it and it can be connected to most other computers.
Yes, if the computer is connected to a network there are options for installing Windows that way.
Sisters.
The components are connected in series (not parallel).
The hard drive is the main, and usually largest, data storage device in a computer. The operating system, software titles and most other files are stored in the hard drive.