When you want to format your windows or when you assemble your computer, you need to Boot your computer from CD/DVD/BD or any USB disk. The CD/DVD you have should be a bootable disk for the booting to be complete.
Having a bootable disk does not allow you to boot from CD/DVD. You should actually instruct the computer to boot from CD. You can do this by changing the boot priority in the BIOS menu.
1. Switch ON your computer or Restart your computer if it is already switched ON.
2. Enter into BIOS.
3. In the BIOS Screen move your arrow keys to select the BOOT option as shown in the image.
4. Then select Boot Device Priority option in the list of options.
You will the list of Boot devices present in your computer and the priority assigned to it.
Note : In this image, the 1st Boot Device is specified as the Hard Disk and 2nd Boot Device as CD – ROM and 3rd Boot Device to Removable Device.
Now when you turn ON your computer, your computer will look for any hard disk connected and try booting from it. If your computer does have any booting information in your hard disk then it looks for CD – ROM and any other removal devices.
So if you are planning to re-install Windows, if you start with Hard Disk as your Boot Device, then your computer will load Windows from it and you will never get an chance to format the windows and install the Windows again.
So we need to change the boot priority to CD-ROM if you are planning to install Windows through the CD/DVD.
5. Press Enter when selecting the 1 st Boot Device.
You will get options to select the drive you want to boot as the first priority. You will need to select CD-ROM if you have planned to install windows from the CD/DVD.
The below image shows how to change in Phoenix BIOS.
You need to press F6 to move a drive up the priority and F7 to move a drive down the priority.
6. That’s it! Now save the BIOS Settings and restart your computer. Now your computer will search CD Drive at the first priority when booting and then moves to the Hard Disk.