you are asking two different questions.
For gaming
you need a good CPU, probably dual core will do it because you are gonna do a lot of work with the PC. also you might need some what kind of a cooler, if you are overclocking your CPU.
Graphic Card , Ram are the important most importing for gaming and web surfing :)
One important hardware component needed for office applications is the keyboard of a laptop or PC. With a keyboard many employees and managers can input information into their systems. Another important component is the monitor. It displays what the user is doing.
Motherboard CPU powersuply and hardrive
Software,and power Anonymous
Software. Short and sweet. Hardware needs software to work.
Gaming and Engineering.
raid card
Generally after a hard drive with enough space to hold your files you need a good amount of RAM. RAM is basically what makes the computer faster, and the types of RAM chips vary from 32 Pin SIMM, 72 Pin SIMM, 168 Pin DIMM, DDR 2 and 3, and all sorts of others.
modem
sir , i am computer hardware engineer, and find job
This unit includes all the hardware needed for a quick and easy installation.
Many hardware stores have in-store guides and plans available for the do-it-yourselfer. They have a complete list of tools needed, hardware needed, and wood needed and associates are there to help answer any questions you may have.