windows 7 - Win 7 ultimate : Trying to install 64 bit version, it keeps giving me the 32 bit version

I've got a very strange problem here.

I have a 64 bit version of windows 7 and I am installing it via a USB drive.

However I keep getting a 32 bit installation instead.

This is why I know it's a 64 bit installation disc (G is where the drive is) :

C:\Windows\system32>dism /Get-WimInfo /WimFile:G:\sources\boot.wim

Deployment Image Servicing and Management tool
Version: 6.1.7600.16385

Details for image : G:\sources\boot.wim

Index : 1
Name : Microsoft Windows PE (x64)
Description : Microsoft Windows PE (x64)
Size : 1,013,548,955 bytes

Index : 2
Name : Microsoft Windows Setup (x64)
Description : Microsoft Windows Setup (x64)
Size : 1,111,336,128 bytes

The operation completed successfully.

I don't even have 32 bit installation files ANYWHERE on my computer or USB drives.

But everytime when I boot via USB and install windows 7 again, it installs the 32 bit version (checked via control panel -> system) and I have less than 4 gb of ram available.

Just what is going on here?

I am using a 32 bit BOOTSECT.EXE to create the USB drive (since the 64 bit BOOTSECT.EXE on the installation disc cannot be run in the 32 bit version of windows that I am stuck with). But it shouldn't change the windows installation, especially considering there are NO 32 bit installation files available.

P.S. The windows DVD/USB tool won't detect my USB drives so I can't use that.