Win8 Install needs Drivers - any help?

Hi All, I have a Lenovo x64 laptop running win7pro.

I am trying to install win8 ent evaluation .iso from Msoft that I burned to a USB-DVD. It gets started and after asking about Languages etc, it pops up an error...
"Windows needs drivers for a media device, it could be a CD, HDD or USB device."

Then it wants me to browse for them. OK, so I quit and ran the Lenovo System update and none of the current drivers needed updating. I manually downloaded all the available drivers including a BIOS (UEFI) Flash which I updated anyway.

I tried again and navigating to where the Lenovo drivers are for USB and Storage, but it can't find any that it is happy with.

Can anyone please help ?

Thanks

When you get to the "Windows needs drivers for a media device, it could be a CD, HDD or USB device." Pop up,
remove the USB Pen Drive & plug in to other port.Than go back to the INSTALL NOW screen, & click on INSTALL NOW .