hi,
I've now noticed that the DVD drive has an exclamation mark next to it in the BIOS but I'm not sure what this means?
maybe, you are talking about device manager but not Bios.
I have changed the boot priority in the BIOS to be CD/DVD first, the windows disk in the CD drive is not seen.
was cd/dvdrom working before a virus attack? are you sure that you insert a bootable windows disk?