Difference between system program and application program?

System Programs or System Software are the programs which enable the computer hardware or system to run (without these the computer as a whole or parts of it's functionality would not work). Examples include the operating system, device drivers.
Application Programs or Application Software are the programs written to for specific applications or execution of specific tasks. e.g. Microsoft Word is an application software for word processing. Internet Explorer and Mozilla Firefox are application software written for internet browsing. Computer games are also application programs.