Hi. My name is***** you for your question and the opportunity to assist.
To install Windows 7 you'll need to make a couple of BIOS changes.
In the Security section, Secure Boot will need to be disabled.
Then go to the Advanced section and open System Configuration.
In there, change Boot Mode from UEFI Boot to CSM Boot. Save the changes
and you should then be able to install Windows 7.
When installing Windows 7, select Custom installation.
Select Drive Options (Advanced), delete all partitions on the hard drive such that the
entire capacity of the the drive shows as Unallocated and apply the change. Click Next and the installation
will take care of the rest.