They suggested
1. Restore Defaults in BIOS.
2. Reset Configuration Data in BIOS.
3. If the CD is detected in BIOS or not,
4. If Yes, can you list the directory in DOS mode, and
5. Cleaning the lens of the CD drive.
6. Reinstalling the drive
7. Updating drivers using windows Update.
Done all that - although not in that order. Still doesn't work.
Sent new e-mail to HP telling them. I think that it's still under warranty - so perhaps they can do something like replace the drive....?