SONY DRU-510A will not recognize DVD's



I have two PC’s. Each one is running XP as the OS. Each one has a SONY DRU-510A DVD writer.

Recently I reloaded each PC with XP. Everything came back working OK, except that the SONY drives will not recognize when I put in a DVD (blank or with data). I can read, and write CDR’s and CDRW’s, but when I install a DVD, and go to My Computer, it does not show any thing loaded. When I run my burning programs (Nero, or Alcohol 120) they say the drive is empty.

I find it hard to believe that both DVD players failed at the exact same time.

HELP !!!