Software is written by software developers using computer-readable code called a(n) a set of instructions that tells a computer what to do, how to do it, and where to send the results or output is called a software replaces small sections of existing software code with new, improved code to add enhancements or fix problems. when you choose a(n) installation, you only install selected features, rather than all of the features associated with a software program. the most important preinstalled software is the software that allows you to use the computer the first time you turn it on. term custom update software system programming language.