Turn on/Restart your computer and once the logo appears, immediately press the Del(ete) key (or F1, F2, F12 Esc, or press Fn + F1/F2/F12 on some laptops). Set the CD/DVD drive (or a removable disk) as a FIRST BOOT DEVICE in BIOS so that your computer can recognise the CD/ DVD or the removable disk which contains the operating-system install files. *If you were unable to access BIOS, just restart your computer and try again, and this time read the line in the lower part of the screen to learn the combination. Once your are in BIOS, use the arrow keys to navigate to Boot (or to Advanced BIOS features on some BIOSes) Navigate to Boot Device Priority (or to First boot device on some BIOSes) Select CD/DVD-ROM (or USB) by pressing Enter and move it upwards using the arrow keys to set it as the first boot device (on some BIOSes navigate to First Boot Device and then make the selection) Press F10 to save the changes and exit BIOS Insert the CD/DVD or the Removable USB and restart the computer. Once you see the following message, press any key on the keyboard Once the Install Windows screen appears, select language, time and currency format, and keyboard or input method and click Next; Click Install now and click Next; Accept the license terms and click Next; Select Custom (Advanced); Select the partition in which you want to install Windows 7 and select Drive options (advanced); Choose a partition, click Format (for every partition separately) and all data stored in it will be deleted and click OK; Select a partition again and click Next; After that, wait for the process to finish. When this is done, you will be prompted to change various settings like language, PC name, network, time and date; Restart your computer and access BIOS to set the Hard Disk as a first boot device;