How to dual-boot/multi-boot Windows 8 with Windows 7
diskmgmt.msc, and press Enter. This will open the Disk Management console. You should see a big (or small) list of all the drives currently attached to your computer.
Windows 8. Don’t change any other settings. This process will format the new partition, which may take a little while.
Installing Windows 8
Windows 8 (or whatever you called it). Be absolutely certain that you’ve selected the right volume, then click Next.