New
#61
USB3.0 DRIVERS + WIN7 INFO UPDATE!
it looks like here is official Dell's manual on how to integrate usb3.0 drivers into the win7 setup image that could be of your interest concerning this your problem:
https://www.dell.com/support/article...en#preparation
or try to install these usb3.0 drivers taken by me from the genuine Dell win7sp1x64pro .iso dated as 2017-04-27