Unfortunately you have to have an original version of PT installed to install the updates.
Did you get in touch with the person that sold you the drive. It should have come with a Plextor DVD that has all the software on it. Or maybe some nice AT denizen here could burn you a copy of the DVD. I have a PX-712 and the software on my DVD is pretty old, but if you can't find someone (preferably the seller) to fix you up...
. And there is a third party replacement for most of the Plextools functionality. You can find out about it on CDFreaks.com . Someone representing himself as Plextor's Euroweenie lawyer tried to shut it down, but I think it's still out there.
.bh.