Help installing Win7 to unallocated disk without losing back up partition?

[Redman0788]

So someone brought me a laptop to work on, as they are having a hard time adjusting to windows 10 and are wanting to go back to windows 7. However there is a partition that contains some of the users data they were hoping to keep, roughly 250GB, labeled as the "backup" partition and about 250GB of unallocated disk space that i'm trying to install windows on. But I get the "cannot install windows to this disk, because its of GPT format", I'm familiar with the "diskpart" command but I dont want to wipe the whole drive clean.

So, my question is: is there anyway I can format the unallocated portion of the disk without losing the backup partition that is on the same disk?

One hard drive, a 500GB disk, 250GB unallocated, 250GB "Backup".

 

[Someone Somewhere]

Go into BIOS and disable 'CSM' and 'Secure Boot' (this is probably already disabled). Next time you boot, it should boot in EFI mode and allow you to install onto a GPT disk.

 

[Redman0788]

I originally had it set up that way, with boot mode selected as "UEFI Boot", not CSM, and secure boot disabled but when windows starts to load off the Win7 disk it hangs up at the Starting windows screeen. So I switched it back to "CSM Boot"/""Secure boot disabled" it allowed me to move on with the installation but I would end up with my original GPT format problem.

 

[Someone Somewhere]

You'll need to find some way to make it boot in UEFI mode. Or copy that backup partition off and clear the drive.