@THEFLASH1932 Thank you very much for your speedy reply. I have tried installing from the same USB stick to another laptop and it worked fine.
It is asking for CD/DVD drivers during the installation process, but on Dell.com I can only find drivers for BIOS, Chipset and Network Adapter. Obviously nothing for CD/DVD seeing as there is no drive on my new laptop.
I will try putting the Chipset drivers on the same Win 7 installation bootable USB I made and see if that makes any difference. I will post my results.
If you have any other recommendations please let me know.