How to change the desktop background ?

Right click on open array of Desktop - Properties/ Personalize - Desktop -  Select Pictures - apply - Ok

• Software :- 

Software is a general team for the viruses kids of programme used to Operate Computers And Related device 

Ex - windows 7, windows 8, windows XP, Microsoft office word, Photoshop print , Doc . 

system Software

System software Is responsible for Controlling, integrating and managing the individual hardware components of a computer system , So that the softwares and the users of the system see it as a Functional unit without having the low-level Details.

Operating system :- 

Operating system is a system Software which is Required for the computer to Start up and it is an interpreter between hardware and user.

Compiler :- 

     A Compiler translates a computer programmer from one language into another, catching any errors in synter along the way, generally translating some High-level language, Such as ctt or COBOL, into optimized machine language.

Application software:- 

An application programme is only a programme designed to perform a specific function directly for the user or in some cases, for another application programme .

Ex- Microsoft office, Point, Tally , Microsoft excel, Photoshop.