virtualbox.org

I have Virtual Box 5.0.4 and have created a Windows 7 VM. I am trying to install Windows 7 Enterprise from CD. When I go to select the drive to install the OS, the setup is not showing a hard disk. I have tried creating a new drive and attaching the drive, but the drive still refuses to appear during the setup process. It is connected as a SATA device.

Go back to the beginning and create a VM from scratch, following the instructions in the manual exactly. That way you will create a hard disk as part of setting up the Virtual Machine.