I bought two new computers for the office last year.  Both are about the size of a box of Kleenex.  Neither has a CD/DVD drive.  I have an external drive but I bought it so long ago, I don't think it connects to these new machines.  Leaving data stored on a computer, even one that is not connected to the Internet, is not the safest form of security.  If you are really worried about that, store the data on a CD, make two copies, keep one in a safe deposit box and the other in a floor safe that cannot be removed from the premises.