Is the CD unreadable because it's scratched, or because the files are corrupted? If it's a regular CD that's scratched then you can buy a CD polisher that polishes out scratches and makes it readable again. Those are pretty cheap and you should be able to buy them at most electrical goods stores. If it's corrupted then you need data recovery software, but I've not found any that works well enough to justify recommending them.
If you're okay with the files remaining unreadable that you're burning, then you could use software like CloneCD that copies everything from one CD onto another including files that are unreadable.
I hope that this helps, but to be honest I'm not sure about the specific nature of your problem.
Basically you just want to burn a file that won't load up when your friend tries to open it. No big deal, just burn the stuff and scratch the CD as bad as you can.
But even if you're successful, he will come back to you for another copy. What you CAN do is give him the wrong files, or change the content so that your code won't run right. Wonder if he would figure out whats wrong, especially because if he could he wouldn't be asking you for it, right?
The best thing to do is to say no.
Get a Hex program and type in random numbers and letters. Save it as the program .cpp or .c or .h w/e. try to open the file it should give you an error. then burn it to a disk and give it to him the more hex you add the bigger the file.
Create an folder with an exe, that opens a messagebox with an error.
Save it as "sourcecode.cpp.exe". If not c++ replace it with the extension of your language (eg. "sourecode.pb.exe")
Rename it to "sourcecode.cpp.pif".
The Icon changes. And the link-arrow appears
Open the properties of the file. Change the Icon to the icon of a cpp-sourecodefile.
sorry but, i dont get it..
and my language is html and php =_="
but if there was no data, then someone will know that the file is 0 byte or empty file. how to corrupting the data ?
i also add some e-book to this cd also, if i using scratched this cd, i fraid the e-book get some error also.
is there to make the error to this code only ??