DVD Rom cannot read blank media

I have one DVD/CD combo, and a Pioneer 107 DVD R/W
Neither of them will recognise blank DVD media.
the combo asks for a disk, and the R/W recognises the media as CD.
Both drives will play DVD movies, (originals and copies).
I had to wipe my HDD and consequently had to reinstall all of the software.
I am now running XP SP2.
I have flashed the BIOS
Updated the firmware on both drives
I have Nero,and Win DVD, but with only one of them it did not work.
Before the upgrade, I had both working perfectly.
The R/W is the master,and the combo is the slave.
Nothing has changed (hardware wise) from before the reload.
Could I ask for some guidance please
TIA