1) You are never going to get away from people making Copies of your CD's. Even if you spent thousands of dollars for research and development to get a technique that would, some young-punk out there is still going to find a way around it.
2) You cannot write back to the CD once the program is installed on a PC. So the CD itself (and the installer contained there-in) wouldn't know how many computer's it has been installed on. To get around this, you'd have to use a method to track when the software has been installed on a computer. In all cases, this is going to force the user to have to have the internet in order to install and the installer will have to send unique Computer information to track about the persons PC. If you allow them to by-pass that when they don't have the internet, then you provide them with a work around for installing on multiple computers which defeats the purpose of what you are doing.
Users almost always feel burdened by copyright restrictions. The more you impose, the more likely that a user will hate your software before he even gets to use it. Even having to enter a CD-key is a burden. If your software never has a need to use the internet, rethink your desire to add copy protection to your deployment.
There are many ways to tackle this topic, no one is going to be a best fit, but knowing what is practical and what is not is more than half of the battle.