You didn't post your Windows version, but if it's Windows XP, the info showing "total size zero" & "free space zero" for a blank DVD is normal because Windows XP does not natively support writing to DVD so Windows Explorer reports all blank ones with incorrect values since it isn't able to read a blank DVD properly.
The values will be reported correctly in Windows Explorer on Windows Vista & Windows 7, because they natively support writing to DVD media without third-party burning software.
You can still write to a DVD on Windows XP using third-party burning software which will recognise a blank DVD correctly.
I know this is an old post but I found it fairly easy googling the same problem that I fixed just now. Unfortunately everyone's advice on this site is usually "buy a new one". That attitude takes all the fun out. Now when dvd drives act like CD drives and not dvd drives it is rarely a throw away the hardware issue.I remember long ago having to fix this in the properties of the dvd drive. First if you go to properties and it says "this device is working properly" then it is. Flip through the different tabs and uncheck "record CD audio" then go to auto play tab and set it up to auto play DVDs, click apply and OK. You should be able to do what I did or something similar and get a message to restart for hardware changes. I'm pretty sure that was the fix working. However I also installed win media codecs pack before rebooting. Upon reboot the drive read as a dvd , read the dvd in it, and worked with ripping software. Now another sign that it is not the hardwares fault is this...my virtual dvd drive created by daemon tools lite also read as a CD drive, clearly a software confusion. This was all on an XP sp2 machine BTW, a new install for a secondary PC for little projects. Also installed XP sp3 before reboot to be accurate. But I tell you I got the reboot for hardware changes after fiddling with properties on drive. And I remember that working back in 2002 when I first got that problem using XP. Hope that helps any future visitors who find this page with similar issues