Well, you have two options...:
1. use a NoCD
You won't need the CD/DVD at all if you do this. For some games (like the GTAs) you'd need to have used a full installation otherwise some elements that load from the CD will be missing.
2. use your CD writing software to make a backup
Nero and others are able to make CD images which you can then mount in Daemon Tools or Alcohol 52%/120%. This in combination with a NoCD will allow you to use a minimum install but still have the entire game content.
You can also then use this image to burn a 1:1 copy. Merely copying and pasting the files and making a new CD from that won't work, but your CD writing software's copying function should.
If your CD burning software is unable to make authentic duplicates you'll need to use a NoCD with the almost-perfect disc it burned for you.
Anyway, hope that helps!
