I literally copied all the files and folders off the install disk, onto an 8GB USB flash drive. I used a similar method to install Windows Vista to a friends laptop. Theirs was newer, so had USB support.
I have tried to use a normal desktop size S-ATA DVD drive, with a S-ATA to USB adapter, but the USB adapter was not recognised either. The actual laptop is fairly up to date in terms of hardware, newest BIOS etc. And there is four USB ports. So I find it odd that there is no native support. Anyway, thanks for the quick reply,