First thing you need to do is locate your Windows Disc! After this you will need to enter your system's BIOS.
To enter your BIOS, start the system and wait to be prompted to hit a key to enter setup. This key is often ‘delete’ ( or ‘del’ ) but it varies depending on the manufacturer. It may be ‘F2’ or another ‘F’ key but the principle will always be the same. The message will be along the lines of ‘hit del to enter setup’.

Once in the BIOS find the option that allows you set the ‘priority boot device’. Refer to your motherboards manual if you are having trouble locating this option. Once you have found the option, set the first boot device to ‘CDROM’

Next insert your system disc and press F10, followed by enter. This will now start the windows installation process.

The first screen that will require interaction. will give you 3 options. All you need to worry about, is the one that says 'Press ENTER to install a fresh copy of windows'. This will take you the legal disclaimer. Follow the instructions and press 'F8' to agree and continue to the next screen.

Next you will need to delete the current partitioned space ( if there is one - there will be if you already have an operating system installed ) Press 'D' to delete the partition and follow through the various keys, hitting them instructed. Now you have a hard drive with an un-partitioned space.

If you only have one hard drive, it is a good idea to create a separate partition for your 'system' data and your personal data. To do this press 'C' with the hard drive highlighted and enter the amount ( which is in megabytes ) you would like to have for your system partition. The recommended amount is between 20000 and 60000 megabytes ( 20-60Gbs )

Now highlight your newly made partition and press 'ENTER'. Select the NTFS NT File system (quick) option and grab yourself a coffee.

The next time the installation process requires your input, you will see a standard Windows XP/Vista window. There will be two buttons, one saying 'Customize' and the other saying 'Details'. Use the option in these buttons to change the settings to your country and time zone. There will be a series of dropdown menus, simply select the appropriate locations etc.

The rest of the screen require simple information, such as date, time and your Computers name. Windows is now installed and ready to go.

Remember to install your Anti-Virus and Firewall before connecting to the internet.