CNET has a free class on how to determine if your computer can play any game. It uses two free programs to access your computer and compare it to the requirement of any game. To check your system go to:
www.gamespot.com/pages/system.reqs/popup.php
and
http://gameadvisor.futuremark.com/gameadvisor/service/my_system.jsp
It recommends monitors, video cards, sound cards. and has other suggestions to speed-up your computer.