I agree with Justchillin69. It's hard for someone to give a solution to a problem when they never encountered the problem. That said, I've trained in IT, and have been doing PC repair work for years. That said, I truly believe this is a glitch with the windows 7/windows Vista systems. I've found that Data DVDs that worked within the last 24 hrs, stopped working on my windows 7 system. It would treat the DVD as empty, attempt to rename it, and even query me on 'how to treat' the disc. The DVD would read absolutely fine on any of my Windows XP systems. The laptop is actually fairly new, and is less than a year old as of the posting date of my reply.
So far, the only solution I've come across is to use the fix it on the Microsoft site.
This will "fix" the problem. However, the fix isn't fool proof, and it sometimes has to be run a few times to take.
After running this fix, it starts reading my Data DVD again as it normally would. However, this isn't a full fix, since I have to keep running this fix every time Windows 7 decides it to read a DVD as blank.
I keep a copy of the fix on my desktop in case it needs to be run again. Unfortunately, as I've mentioned, it's not a full fix, but can be similar to Justchillin69's.
Microsoft offers it for free, so I advise those who still have the problem to give it a whirl. Again, no guarantees, but it worked for me.