Common sense should tell you that if you sell/give away the CD you
> should delete any copies you have of it. That is the same rule for
> computer software, you have the right to make a copy but once you no
> longer own the original, you have to delete any copies you have for > backup.
Common sense may tell you that, but in my jurisdiction you'd be very wrong.
Of course, common sense would tell you that when I burn my own singing to a CDR, I shouldn't have to pay the music industry.
Since I do one, I do the other without any moral or ethical objection.
Before posting legal advice please take the time to investigate where the person asking the question is located since their jurisdiction may have vastly different rules then yours.