How to make computer

To build a computer that functions, you only need-

-a Hard Drive
-a Processor with fan and heatsink
-a motherboard
-a Monitor
-256mb or more of ram
-a Power Supply Unit-(PSU)
-a mouse
-a keyboard
-cables to connect it all

But to add form to function you need, in addition to that above-

-a case - AT, ATX, BTX, or LPX -a modem
-an ethernet card
-CD/DVD drives

and if you want it to be even better-

-a graphics card 
-a sound card
-speakers
-another hard drive