Bootcamp WIndows 7 can't get pass installation because keyboard won't work

Hello Apple Community 😀

I am in a bit of an impass, and the past few weeks have been ponctuated with a lot of work to solve my problem.

I am trying to install Windows 7 (Professional 64 bits) on my Late 2013 21.5inch iMac, and have been struggling with the first step : Windows installation.

Here's the problem : I am able to boot up on WIndows OS after partitionning my hard drive (Using Bootcamp 5), and I checked the "Install latest windows drivers". WIndows loads up, I use a USB key as my Boot Drive, and my first attempt, Keyboard and Mouse don't respond. Even if I change usb port, put the Boot USB Key in another port, and even praying to the Bootcamp Lord won't do anyhing 😟

At last, I redo the whole thing after reading that the order of the Bootcamp setup (Make a Windows Boot-up Key, check the latest driver and AFTER Partition the Hard Drive in another process) and guess what ! IT WORKS ! Windows Boots up, the files decompress into my hard drive, and even get Windows in my OS choices if I hold Alt at the Mac boot-up. But then, when it comes to the time of giving a name to the computer and other (Which is still in the installation process, but doesn't require the USB Key because Windows is officialy installed) Keyboard and Mouse doesn't respond. Nothing,

I have the latest drivers installed in my windows support files on the USB key, and Keyboard worked when I was in the file installing process, so My only guess is that because the USB Key had the latest drivers, The first phase of the installation worked but when I am using windows "officialy" on my hard drive, the drivers just haven't installed.

Can't install drivers because I am still on intallation process, and can't access Safe mode because I am STILL IN THE INSTALLATION PROCESS.

Help me please 😮 😮 😮