You want to make a DUAL BOOT (Windows 8 and Windows 7 - 64 bit) on your hard drive without having to erase your current data, this can be achieved ona computer with a UEFI motherboard and hard drive in the GPT format:
- To begin, disable the secure boot feature in the BIOS of your motherboard and enable BIOS legacy mode.
- You will then need to change the UEFI boot order, putting the CD/DVD ATAPI drive first.
Create a partition
- Right click on your "My Computer" and select "Manage".
- A new window should appear. In the Disk Manager search for "Disk 0" and select the partition you want to divide (normally the one on which your current OS is installed)
- Right-click > Shrink.
- Select the size of your new partition.
- Your new partition will appear as unallocated space.
- Right-click the partition and select "New Simple Volume", which should bring up a new wizard to create a simple volume.
- Choose a drive letter (G:, H:, etc ...) and follow the onscreen procedure to finalize the creation of your new partition.
The commands to be entered
Open the command prompt (Run > type "cmd") and run the following commands:
- Type "DISKPART" and confirm with Enter.
- DISKPART should then open, type "SELECT DISK 0" a and confirm with Enter.
- A message stating that disk 0 is selected should be displayed.
- Now type DETAIL DISK and press enter: The volumes present will be listed.
- Then locate the volume that you created earlier and enter "SELECT VOLUME volume_number" and press Enter.
- DISKPART would then indicate that the volume has been selected.
- Type AUTOMOUNT and press Enter
- DISKPART will then tell you that the automatic mounting of new volumes enabled.
- Finally you need to type EXIT to exit DISKPART and close the CMD window.
- Now you should be ready to install a new operating system.
Installing the new OS
Note that: you must use the 64-bit versions of Windows for GPT formatted drives
Simply insert the installation DVD of Windows 7 and run from the desktop. During installation, you must choose the volume that you have created earlier.
Thanks to toto13015 for this tutorial.