E5470 Universal Serial Bus Controller

Are you trying to do this to install WIndows 7, or for a more current OS?

If this is to install Windows 7, realize that Intel and Microsoft removed the USB 2.0 support from the chipset and MIcrosoft hasn't (and will not be) adding the ability to do a USB 3.0 boot to Windows 7 -- effectively, Skylake is an opening act in the death scene for Windows 7 (the Fall-arrival of Kaby Lake will be the end of 7, as that chip/chipset will not allow anything older than Windows 10 to be installed).

ASUS has a pretty good tutorial on how to work around the Skylake-Windows 7 support issue here:

www.asus.com/.../

You're going to need to produce a custom install image of Windows 7-64 bit to get this to work, with the Intel USB drivers slipstreamed into it.  The ASUS method is one way - there are plenty of others out there, starting with the Windows Zero Admin kit, RT7 Lite, etc.  

However, you may want to (or have your company) evaluate its reasons for keeping Windows 7 -- this is the very last generation of Intel hardware on which you'll be able to run Windows 7 at all.  Starting late this year as Kaby Lake takes over, you'll need to start switching to Windows 10 or stop buying new hardware.

Dell's official route is here

http://www.dell.com/support/article/us/en/04/SLN300564