In order to make a personal back up copy of your game, you of course need the original game cd and a CD burner. Many developers will put a key (encryption) on the CD itself to deter people from 'stealing' or making illegal copies. encrption keys like Securom and Laserloc are just examples.
In order to break that encrption, you need a burning software like Clone CD or Alcohol to make a perfect copy. Depending on the version of the encrption, it may or may not make a perfect working copy.
Sadly, i found out recently they discontinued Alcohol as well.... it wasn't too long ago Clone CD went under... dayem... now what the hell are we supposed to use??... good god... those darn corporate lawyers are MUCKING UP the good work these software companies are doing!@@#!$
Yeah that's probably cuz you didn't know about the encryption key and probably used a lame cd burner. I had that problem about 3 years ago when i didn't know about this stuff and made a couple of coasters.
alcohol 120 is a good bet. Clone the cd and burn it. Then make sure you have the cd-key. Then search the net and download a crack for the game.
***ANNOUNCEMENT***
If you want a game go buy it and dont rip of the companies that publish the games otherwise the company will go out of business and no longer be able to produce such beautiful forms of entertainment