how can I dual boot win10 with win7 using win7 system image

I upgraded to win 10 on my pc
bt I discovered my gaming is too slow,
so I want to install win 7 through a
system image I created on my second
pc( the same type and specs but
different username and o.s since I
upgraded my main pc from win7 to
win10) onto the new partition I
created on the pc ( for the win7
installation). The external hd I used
to create the image was western
digital hd bt its not showing in the
'select usb drive' when trying to
restore the image.
Edit:: I actually want to dual boot
win10 and win7

I upgraded to win 10 on my pc
bt I discovered my gaming is too slow,
so I want to install win 7 through a
system image I created on my second
pc( the same type and specs but
different username and o.s since I
upgraded my main pc from win7 to
win10) onto the new partition I
created on the pc ( for the win7
installation). The external hd I used
to create the image was western
digital hd bt its not showing in the
'select usb drive' when trying to
restore the image. I used windows backup to create the system image.

Edit:: I actually want to dual boot
win10 and win7

hello, and welcome to win10 forum.
if I'm reading you right ,it not legal according to Microsoft to use the same win7 that you already used to upgrade other computer to win10 , but I maybe miss reading you text . anyway check out his tutorial by Brink

Windows 10 - Dual Boot with Windows 7 or Windows 8 - Windows 10 blog

hello, and welcome to win10 forum. if I'm reading you right ,it not legal according to Microsoft to use the same win7 that you already used to upgrade other computer to win10 , but I maybe miss reading you text . anyway check out his tutorial by Brink Windows 10 - Dual Boot with Windows 7 or Windows 8 - Windows 10 blog

Thanks so much for the link. I eventually ditched the system image and bought win7 installation disk to create fresh install and dual boot with win10. While installing it didn't allowed me to install. I thought i can run diskpart clean on one partition, selected one volume and ran clean command, but it still cleaned all the partitions and data. I cannot boot my win10 (since its all wiped) until I install OS on freshly created single partition. I was told to use partition recovery apps like partition and mount software to restore my partitions and files . Do I have to install win7 on it anyways and once its installed, instal the partition and mount software for the recovery? Or do you have better option? Thanks in advance

NO! Don't do anything that involves the hard drive at this point. You will need to use another computer to create a disk recovery boot disk from a recovery program and use that to boot the computer with the affected hard drive and then let the program do its thing.

This is the program I have used in the past, and I think Brink recommends it too:
Active@ Partition Recovery restores deleted damaged volumes &amp disks. Freeware Data Recovery Software Toolkit

You can try this one for free, the company is a pretty good company, but I haven't used this software:
Free Partition Recovery Software - EaseUS Partition Recovery.