Help for a novice???

Please help me understand whats going on with cd's. I use Adaptec easy cd creator which came with my new dell computer. I have a sony writer and a samsung reader. I can make backups of my CAD programs and any other stuff with absolutly No problems. PSX games are a little trickyer but PC games seem impossible for me. If You are simply copying the data from one cd and making a replica cd how does a PC know the difference???? why are patches required??? are there files which the computer WONT copy?? when trying to make backup of unreal tournament it says it cant read sectors 810 to 836 and illegal command request????
PLEASE HELP ME UNDERSTAND WHATS GOING ON!!!!!