If the laptop you plan to install a new operating system, you will need a disk or a flash-map of its distribution. Go into the BIOS of the laptop (press F2, F9 or F10 before boot) and log to the tab "Boot Device". In this tab you need to set the sequence of devices from which will be downloaded to the operating system. Depending on the medium on which is recorded the distribution of Windows, put the first CD-ROM or USB-drive.
Insert the disc in the drive (the flash drive into the USB port). Then to begin installation. Wait while the installer copies files. You will then have to choose how to go through the process of installation: on top of the existing system or on a formatted disk.
Carefully follow the installation process where you choose the options you require, including regional. During the installation process and after it, the computer may restart several times. The appearance of the desktop operating system means the completion of the installation. For okonchanii installation remove the removable media from which it was made, and then on that computer, install all the necessary drivers and software.
Installing Windows over an existing copy has two versions: installing a new operating system and upgrade your existing. Choose the most suitable for your situation.
If you decide to install Windows again, format the disk, saving all the necessary data on the archive logical drive.