8 Krypton

RE: We have a Dell Precision 3510 Laptop and no matter what was done we could not install an O/S from DVD or USB.

There's no way this was done and tested over a remote connection -- it requires the use of a working system (not the one in question).

You must prepare an updated Windows 7 boot medium as an ISO and inject the USB 3 drivers as noted.

Other issue:  Whatever your business reasons for keeping Windows 7 vs. 10, note that the Fall release of Kaby Lake CPUs will require rethinking them -- the new seventh generation Intel CPUs won't run any Windows release older than 10, so you'll soon be faced with a decision:  keep the old OS and buy old hardware, or upgrade to Windows 10 if you want to keep purchasing new hardware.