After updating the firmware of my Plextor PX-708A to 1.08, the drive letter changed places with a harddisk. It insisted on being drive D. I got it back to drive F where it belongs. But it seems that Nero (and other burning tools) now only sees it as a CD burner. Nero will not allow burning DVDs anymore.
I have tried downgrading the firmware to 1.07 and reinstalling the hardware in WinXP - but still only CD burning is offered.