Windows 7 Pro 64bit reinstall - CD/DVD drive not found

Hi guys,
Wondering if any one can throw any more ideas my way on this one.

I have a Sony Vaio VGN-NR11s which has been running a retail boxed version of Windows 7 Professional 64bit fine since its release.

My system was a mess, updates stopped working, got some viruses so decided to format the drive and start again.

So I have an empty 250GB HDD, BIOS has been set back to defaults (no option to switch between IDE and AHCI.
I pop the disk in and boot, all appears to be fine. It boots from the disk and I get the Install screen after several minutes (proving that the cd/dvd drive is working).

When I select "Install now" the disk starts up but then keeps spinning down and clicking.
It gets past the "set-up is starting", after about 15 minutes of doing nothing it tells me that the cd/dvd driver hasn't been found.

I have copied the Windows 7 optical drive driver from a working machine onto a usb stick and tried to point the set-up process to this when it asks for the driver, but its says there is no information in the file.

I have also copied the entire Windows 7 set-up cd to an external drive to see if it will pick it up but still nothing.

Is there anything else I could try? I don't have a spare usb stick large enough to install from.

Don't worry guys I found a work round...a usb cd/dvd drive. Will tackle the issue with the built on drive one I have installed Windows. Thanks.

In addiition, try to stick closely to the same steps given here for Clean Reinstall - Factory OEM Windows 7 which contains the best practices for getting and keeping a perfect reinstall. The latest official installer and tool to write to stick is also there.