Hi Richardbrodie,
Why you want to downgrade it to 7....if there is performance issue you can do a clean installation
If you still want downgrade do as below:-
If its an OEM Windows 10 Pro license that came preinstalled, yes, learn how:
https://www.groovypost.com/howto/downgrade-windows-10-to-windows-7-windows-81/
if not, so you would need to backup all your files, clean install Windows 7 and then re-install all your software . . .
The Windows 7 product key should be o a Sticker on the bottom casing of your PC/Laptop If it is a laptop, or it might be under the battery - you will need it!
Backup all your files
Click this link to download the Windows 7 ISO file
https://www.microsoft.com/en-us/software-download/windows7
Click this link to download a small Microsoft utility (Windows USB/DVD Download Tool) to create bootable Installation Media from the ISO
https://support.microsoft.com/en-in/help/15088/windows-10-create-installation-media
Create the bootable Installation media on a DVD or USB Flash Drive
Insert the bootable media into the PC
Start your PC, on the manufacturer's logo screen press the appropriate button to get into BIOS Setup (Usually F2 or Del key)
or press F12 when you start PC
Move the drive with the bootable media to the to of the Boot order list
Press F10 to save settings and restart
Windows 7 will begin installing
When your system reboots, go into BIOS and set your hard drive as top of the Boot Order
Do not remove the Installation media until you reach the Desktop
Thnaks
Kumar A.
FYI:
Microsoft does NOT supply Windows 7 ISO downloads for OEM preinstalled product keys for a Dell, HP, etc. machine.
