|"My elder brother once tried to format the XP Software"|
Formatting erases the hard drive & sets up a file system to be used for installing an OS or for storage. If he successfully formatted, there's no OS to boot into.
List your complete specs or the make/model of your system. Are there any beeps at startup? Is anything displayed on the screen before the blinking cursor appears? Can you enter the BIOS? If you can, have you checked to see if the hard drive is being recognized?