Desktop Installing Windows 7 Question

Hello all

First off I know this is a notebook forum but you guys know your stuff and I have used this site many many times to get the answers I have needed. Anyways as you can see in my sig. I have a Gateway desktop and notebook. I have installed Windows 7 without a problem on my notebook however when trying to install it on my desktop this is where I run into an issue. Ohh by the way this is a fresh install and not an upgrade.

After booting from the disc and getting to the install window, I click on "Install Now" than it comes to the next screen where this pops up, it says "A required CD/DVD drive device driver is missing. If you have a driver floppy disk, CD, DVD, or USB flash drive, please insert now.
Note: If the Windows installation media is in the CD/DVD drive, you can safely remove it from this step."

My options are Browse, Ok, Cancel

If I press Ok it says "No device drivers were found. Make sure that the installation media contains the correct drivers, and then click OK."

I have no idea what they are wanting. My desktop didn't come with a drivers disc if I can remember. And on the Gateway website there is nothing for Windows 7 just Vista. I am also upgrading from 32 bit Vista Home Prem. to Windows 7 Ult. 64bit

My desktop is a modded (New Case, more RAM, GPU, extra HD) Gateway GM5478