Cases come in all sizes and shapes from the small foot print on the desk to the
convertible mini tower to the full tower case.
The case houses all the components of the computer, motherboard (or main board)
power supply, floppy drive (almost obsolete!), hard drive(s), CD ROM or DVD ROM,
sound card, video, and network card. Some computers have other specialty cards
also.
A properly designed case will have adequate cooling as part of the design, it
may come from the factory with extra fans all ready installed or have specific
places to add more fans.
The case will have three main sections:
1) The motherboard bay
2) The power supply bay
3) The drive bay
If you are considering upgrading or
building your own computer consider the
function of the
computer. Research the components you want to have in the computer, there is
nothing
worse than buying a case and finding out that the "dream" main board you have
bought will not fit.