Windows 7: Problem converting GPT parition to MBR on Windows 7 Setup

Hello everybody,
Today I wanted to reformat my computer with Windows 7 because he was very slow. So I took an official Windows 7 DVD Rom and I started my installation. When I was in the window "Where do you want to install Windows ?" I choosed my partition with 441 GB and I pressed on "reformat" and I had the error "Windows cannot be installed to this disk. The selected disk is of the GPT partition style".

So I searched on the Internet, and I went to a topic on your website (Convert GPT Disk to MBR Disk) and I did all the steps. The problem is that when I do the command "convert mbr" it says me "The specified disk is not convertible. CD-ROM and DVD are examples of non convertible disks".
Maybe I have this error because I don't removed the volume "System" and "Recovery" but I don't think it's a good idea to remove them.
I let some screenshots:







Thank you if you can reply and sorry for my bad english,

Rémi.

I would go will GPT.
You need to use a GPT setup.
You need to do a clean install,
As the new MOBO's now have a uEFI BIOS.
How to install Windows 64 bit on a uEFI BIOS:
UEFI (Unified Extensible Firmware Interface) - Install Windows 7 with

Make the OS HD DRive first in Drive Options



To boot your DVD, use boot menu



press enter on the UEFI DVD drive

Doesn't work ...

Are booting from the UEFI DVD Drive ?

Oh yes it worked ! :d
thank you so much !

You are welcome.