COMPUTER VIRUS

• Computer virus are programs that spread across computers by attaching a copy of itself to the files on the infected computer.
• When the infected file is run, the virus gets into action.
• A virus is usually harmful and can corrupt data, overwrite files, or use up system resources, and slow it down in the process.
• Some may be merely disturbing like sending email using address book.
• Viruses are written by programmers to cause trouble.

HARDWARE AND SOFTWARE OF A COMPUTER

HARDWARE:
The components of the computer, which we can see, feel and touch, are known as the hardware.
Hardware comprises all the peripherals, which are associated with the computer.

SOFTWARE:
Software is a collection of Programs and instructions, which handle the different components of your computer and help them to interact in a hassle-free manner. Without software, a computer is nothing but a box with components that does not serve any purpose.
Computer software can be broadly classified into two categories viz:
(a) system software (operating system)
(b) application software(utility software)

SYSTEM SOFTWARE :
System software is the collection of programs and instructions designed to control, co-ordinate and extend the processing capabilities of a computer system. These programs act as an interface between the user and the computer.

APPLICATION SOFTWARE:
Application software are programs designed to use computer for a specific task. These programs are written to meet the needs of the user as the demand arises. Application software cannot function without system software. They give the user the flexibility to use the computer for special applications by providing with tools, which are otherwise not available with the system software. Examples of application software include Microsoft office, office XP, Adobe package, flash etc.

DISK OPERATING SYSTEMS:
Disk operating system is the operating system for personal computers (PCs).DOS provides a set of commands that enable to access or manipulate information on disks as well as simply interact with the PC. DOS manages file operations (copying, printing, viewing etc) disk storage organization, screen displays and other routine tasks that help make a PC easier to use. Software itself is contained on a disk and generally is loaded from that disk each time the computer starts up or boots.